WO2021009979A1 - Light detection device - Google Patents

Light detection device Download PDF

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Publication number
WO2021009979A1
WO2021009979A1 PCT/JP2020/014627 JP2020014627W WO2021009979A1 WO 2021009979 A1 WO2021009979 A1 WO 2021009979A1 JP 2020014627 W JP2020014627 W JP 2020014627W WO 2021009979 A1 WO2021009979 A1 WO 2021009979A1
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Prior art keywords
region
photodetector
electrode
semiconductor substrate
layer
Prior art date
Application number
PCT/JP2020/014627
Other languages
French (fr)
Japanese (ja)
Inventor
嵩宏 濱崎
裕行 高篠
侯治 永廣
洋征龍 大理
宮田　里江
三浦　隆博
尚郎 吉村
Original Assignee
ソニーセミコンダクタソリューションズ株式会社
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Application filed by ソニーセミコンダクタソリューションズ株式会社 filed Critical ソニーセミコンダクタソリューションズ株式会社
Priority to US17/624,887 priority Critical patent/US20220278141A1/en
Priority to CN202080043616.0A priority patent/CN113994482A/en
Priority to JP2021532678A priority patent/JPWO2021009979A1/ja
Priority to EP20840487.1A priority patent/EP3998641A4/en
Priority to KR1020217041242A priority patent/KR20220030939A/en
Publication of WO2021009979A1 publication Critical patent/WO2021009979A1/en

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Definitions

  • This disclosure relates to a photodetector.
  • photodetectors that can be used for both imaging and sensing have been proposed.
  • a photodetector that detects the amount of incident light as a dynamic change in current or voltage has been proposed (for example, Patent Document 1).
  • Such a photodetector can operate as a photon count sensor, a ToF (Time of Flight) sensor, or the like.
  • the optical detection device includes a plurality of photoelectric conversion units provided on the semiconductor substrate, and the photoelectric conversion units are of the first conductive type provided on the first surface side of the semiconductor substrate. Between the first region, the second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and the first region and the second region of the semiconductor substrate.
  • a third conductive type third region that is provided in the region and absorbs incident light, extends from the second surface in the thickness direction of the semiconductor substrate, and is electrically connected to the first region at the bottom surface. It includes a first electrode, an insulating pixel separation layer provided on the side surface of the first electrode, and a second electrode that is electrically connected to the second region from the second surface side.
  • the photodetector according to the embodiment of the present disclosure is provided in the first region of the first conductive type provided on the first surface side of the semiconductor substrate, and on the second surface side opposite to the first surface of the semiconductor substrate. It is provided in a second region of the second conductive type and a region between the first region and the second region, and includes a third region of the third conductive type that absorbs incident light.
  • the first electrode extends from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate and is electrically connected to the first region at the bottom surface, and the second electrode is It can be electrically connected to the second region from the second surface side of the semiconductor substrate.
  • a wiring layer electrically connected to the first electrode or the second electrode can be provided on the surface of the semiconductor substrate opposite to the light incident surface.
  • FIG. 28 It is a timing chart diagram which shows an example of the operation of the ToF sensor of the photodetector which concerns on this embodiment. It is explanatory drawing explaining the light source used for the ToF sensor. It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (1) of FIG. 28. It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (2) of FIG. 28. It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (3) of FIG. 28. It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 1st modification.
  • FIG. 117A It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 2nd variation. It is a vertical sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 118A. It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 118A. It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 3rd variation. It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 119A.
  • FIG. 1 is an explanatory diagram schematically showing a basic configuration of a photodetector 10 according to the present embodiment.
  • FIG. 2 is a schematic graph showing the current-voltage characteristics of the photodetector 10.
  • FIG. 3 is a graph showing a change in the polarity of the bias voltage applied to the photodetector 10
  • FIG. 4 is a graph showing the delay of the current flowing from the photodetector 10 in response to the change in the polarity of the bias voltage. is there.
  • the vertical direction or the vertical direction means the thickness direction of the substrate or the layer.
  • the lateral direction or the left-right direction means one direction in the plane of the substrate or layer (for example, the cutting direction of the substrate or layer in the cross-sectional view).
  • the photodetector 10 includes a first region 11, a second region 12, and a third region 13 provided between the first region 11 and the second region 12. To be equipped with.
  • the first region 11 is, for example, a first conductive type (for example, N type) semiconductor region electrically connected to a ground or the like.
  • the second region 12 is a second conductive type (for example, P type) semiconductor region electrically connected to an electrode whose applied voltage can be controlled.
  • the third region 13 is a third conductive type (for example, type I) semiconductor region provided between the first region 11 and the second region 12 and absorbs incident light.
  • the photodetector 10 is a so-called PIN diode, and as shown in FIG. 2, the voltage-current characteristic greatly changes depending on the polarity of the applied bias. Specifically, since a negative voltage is applied to the second region 12, a reverse bias is applied, so that almost no current flows between the first region 11 and the second region 12 regardless of the applied bias voltage. Absent. On the other hand, in the forward bias state in which the positive voltage is applied to the second region 12, the forward bias occurs. Therefore, as the applied bias voltage increases, the current suddenly flows between the first region 11 and the second region 12. Will flow.
  • the photodetector 10 can estimate the intensity of the incident light by measuring the delay time of the current increase when the polarity of the applied bias is changed.
  • a photodetector 10 is also referred to as, for example, a DPD (Dynamic Photodiode) sensor.
  • 5A to 5C are schematic graphs showing an example of the relationship between the light incident on the photodetector 10 and the delay time of the current increase with respect to the change in the bias voltage.
  • the photodetector 10 when light is not incident, the photodetector 10, the delay time of the current increase for a polarity change of the bias voltage is assumed to be t 1.
  • the delay time of the current increase with respect to the change in the polarity of the bias voltage becomes t 2 , which is shorter than t 1 .
  • the photodetector 10, that the intense light than in the state of FIG. 5B is incident as shown in FIG. 5C, the delay time of the current increase for a polarity change of the bias voltage and the shorter t 3 than t 3 become. Therefore, according to such a photodetector 10, the amount of incident light can be calculated by measuring the time from the change in the polarity of the bias voltage to the increase in the current.
  • FIG. 6 is a vertical cross-sectional view showing a more specific configuration of the photodetector 10.
  • FIG. 7 is a graph showing a change in current with respect to a change in bias voltage.
  • 8A to 8D are vertical cross-sectional views showing the movement of electrons and holes of the photodetector 10 at each timing of FIGS. 7 (1) to 7 (4).
  • 9A to 9D are graphs showing the energy band structure at the AAA cut surface of the photodetector 10 at each timing of FIGS. 7 (1) to 9D.
  • the photodetector 10 includes, for example, a first region 11, a second region 12, a third region 13, a first electrode 21, a first surface insulating layer 16, and a pixel separation layer.
  • a 15, second electrode 22, a control gate 25, and a gate insulating film 26 are provided.
  • the first region 11 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 12 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the third region 13 is a third conductive type region (for example, layer i) provided between the first region 11 and the second region 12 of a semiconductor substrate such as silicon (Si).
  • the first electrode 21 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 16, and is electrically connected to the first region 11 via a via or the like penetrating the first surface insulating layer 16. To do.
  • the first electrode 21 functions as, for example, a cathode electrode.
  • the pixel separation layer 15 is provided with an insulator penetrating the semiconductor substrate in the thickness direction.
  • the pixel separation layer 15 is provided, for example, to electrically separate each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other.
  • the second electrode 22 is provided on the second surface of the semiconductor substrate and is electrically connected to the second region 12.
  • the second electrode 22 functions as, for example, an anode electrode.
  • the control gate 25 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 26.
  • the control gate 25 is provided to control the height of the potential barrier PB described later in the third region 13 by applying a voltage.
  • the first electrode 21, the second electrode 22, and the control gate 25 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalu (Ta), and polysilicon (Ta). It may be provided with poly—Si) or other conductive material.
  • the first surface insulating layer 16, the pixel separating layer 15, and the gate insulating film 26 are insulators such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. It may be provided at.
  • the voltage applied to the first electrode 21 is Vc
  • the voltage applied to the second electrode 22 is Va
  • the voltage applied to the control gate 25 is Vg.
  • the photodetector 10 controls, for example, the voltage Vc of the first electrode 21 to 0V, and controls the voltage Va of the second electrode 22 and the voltage Vg of the control gate 25 to -1V. It can be controlled to reverse bias mode.
  • the optical detection device 10 is set to the forward bias mode by, for example, controlling the voltage Vc of the first electrode 21 to 0V and controlling the voltage Va of the second electrode 22 and the voltage Vg of the control gate 25 to + 1V. Can be controlled.
  • the energy band structure of the photodetector 10 at this time has a structure in which the second region 12 side is high and the first region 11 side is low, so that the third region 13 is in a depleted state.
  • a potential barrier PB is generated in a region adjacent to the first region 11 and the second region 12 as shown in FIG. 8B.
  • the energy band structure of the photodetector 10 at this time has a structure having a concave or convex potential barrier PB between the first region 11 and the second region 12.
  • the flow of electrons e and holes h in the three regions 13 is obstructed, and almost no current flows through the photodetector 10.
  • the third region 13 in which the electrons e and holes h obtained by photoelectrically converting the incident light are depleted. Occurs in.
  • the energy band structure of the light detection device 10 as shown in FIG. 9C, the height of the potential barrier PB is lowered by the electrons e and holes h that are photoelectrically converted from the incident light.
  • the electrons e gradually flow out from the first region 11 or the holes h flow out from the second region 12, so that the height of the potential barrier PB is further lowered by the flowed out electrons e and holes h.
  • the potential barrier PB generated in the regions adjacent to the first region 11 and the second region 12 disappears, so that the photodetector 10 sequentially A current in the direction will flow. That is, as shown in FIG. 9D, the energy band structure of the photodetector 10 at this time is a substantially flat structure in which the concave or convex potential barrier PB existing between the first region 11 and the second region 12 disappears. It becomes.
  • the photodetector 10 can measure the incident amount of light by measuring the time until the potential barrier PB disappears in the time until the forward current starts to flow.
  • the pixel corresponds to a specific example of the "photoelectric conversion unit" in the present disclosure.
  • FIG. 10 is a vertical sectional view showing the basic structure of the photodetector 300 according to the present embodiment
  • FIG. 11 is a plan view from the first surface side showing the basic structure of the photodetector 300 according to the present embodiment. Is.
  • the photodetector 300 includes, for example, a first region 310, a second region 320, a third region 330, a first electrode 311 and an upper first electrode 312, and a pixel separation layer 351.
  • the upper pixel separation layer 352, the first surface insulating layer 353, the second electrode 321 and the control gate 361, and the gate insulating film 362 are provided.
  • the first region 310 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the first region 310 is an upper pixel separation provided on the first surface of the semiconductor substrate and the side surface of the upper first electrode 312 (details will be described later) extending from the first surface of the semiconductor substrate in the thickness direction of the semiconductor substrate. It is provided in a region along the layer 352.
  • the second region 320 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the semiconductor substrate such as silicon (Si).
  • the third region 330 is a third conductive type region (for example, layer i) provided between the first region 310 and the second region 320 of a semiconductor substrate such as silicon (Si).
  • the first electrode 311 is provided at the boundary of each pixel extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, and is provided at the upper first electrode 312 and the bottom surface, which are smaller in width than the first electrode 311. Contact.
  • the upper first electrode 312 has a width smaller than that of the first electrode 311 and is provided extending from the bottom surface of the first electrode 311 to the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate.
  • the width of the first electrode 311 is larger than the width of the upper first electrode 312, a part of the bottom surface of the first electrode 311 in contact with the upper first electrode 312 is covered with the upper first electrode 312. I won't be able to. Therefore, the first electrode 311 can be electrically connected to the first region 310 provided along the side surface of the upper first electrode 312 at a part of the bottom surface of the first electrode 311.
  • the first electrode 311 and the upper first electrode 312 function as, for example, a cathode electrode, and are electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
  • the first electrode 311 and the upper first electrode 312 have, for example, a first opening penetrating the semiconductor substrate from the second surface to the first surface in the thickness direction, and an opening width larger than that of the first opening, so that the semiconductor substrate can be formed. It can be formed by embedding a second opening that is dug halfway in the thickness direction with a conductive material. That is, the upper first electrode 312 may be formed by embedding a conductive material in the first opening, and the first electrode 311 may be formed by embedding a conductive material in the second opening.
  • the pixel separation layer 351 is provided on the side surface of the first electrode 311 and the upper pixel separation layer 352 is provided on the side surface of the upper first electrode 312.
  • the pixel separation layer 351 and the upper pixel separation layer 352 display the upper surface of the step of the first electrode 311 and the upper first electrode 312 with respect to the first region 310 among the first electrode 311 and the upper first electrode 312. Can be exposed. Therefore, the pixel separation layer 351 and the upper pixel separation layer 352 electrically separate the photodetectors 300 provided adjacent to each other in the in-plane direction of the semiconductor substrate from each other, and set the first electrode 311 in the first region. It can be electrically connected to 310.
  • the first surface insulating layer 353 is provided on the first surface of the semiconductor substrate.
  • the first surface insulating layer 353 can protect the semiconductor substrate including the first region 310 from the outside world, for example.
  • the photodetector 300 can increase the aperture ratio on the first surface, which is the light incident surface.
  • the second electrode 321 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 320.
  • the second electrode 321 functions as, for example, an anode electrode and is electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
  • the control gate 361 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 362.
  • the control gate 361 is provided to control the potential barrier in the third region 330 by applying a voltage.
  • the first electrode 311, the upper first electrode 312, the second electrode 321 and the control gate 361 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), tantalum (Ta) or the like. It may be provided by the metal, polysilicon (poly-Si), or other conductive material.
  • the pixel separation layer 351, the upper pixel separation layer 352, the first surface insulating layer 353, and the gate insulating film 362 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or so-called low-. It may be provided with an insulator such as k material.
  • the photodetector 300 is provided as a back surface (that is, the first surface) irradiation type CMOS (Complementary MOS) image sensor, so that the aperture ratio on the back surface side, which is the light incident surface, can be increased. it can.
  • the light detection device 300 uses the first electrode 311 extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, so that the second surface side of the semiconductor substrate is relative to the first region 310.
  • the cathode electrode can be electrically connected from. Therefore, the light detection device 300 is provided with various electrodes and wirings electrically connected to the first region 310 and the second region 320 on the surface (that is, the second surface) opposite to the light incident surface of the semiconductor substrate.
  • the aperture ratio of the back surface (that is, the first surface) which is the light incident surface can be increased.
  • the photodetector 300 since the first region 310 and the second region 320 are arranged in the thickness direction of the semiconductor substrate, the occupied area can be made smaller. According to this, the photodetector 300 can miniaturize the pixels more efficiently. Further, the photodetector 300 according to the present embodiment can suppress crosstalk between pixels by the pixel separation layer 351 and the upper pixel separation layer 352 extending in the thickness direction of the semiconductor substrate, so that noise can be further reduced. It can be reduced.
  • FIG. 12A is a vertical cross-sectional view showing the structure of the photodetector 300 according to the first variation.
  • FIG. 12B is a plan view of the photodetector 300 according to the first variation as viewed from the second surface side.
  • the first electrode 311 is provided so as to surround the entire circumference of the rectangular region corresponding to the pixel, and the pixel separation layer 351 is inside the rectangular shape of the first electrode 311. It is provided along.
  • the second region 320 may be provided, for example, in an island shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351.
  • the control gate 361 and the gate insulating film 362 may be provided, for example, so as to surround the second region 320 in the in-plane direction of the semiconductor substrate.
  • the photodetector 300A can make the occupied area smaller by arranging the first region 310 and the second region 320 in the thickness direction of the semiconductor substrate. Further, the photodetector 300A can suppress crosstalk between pixels by providing the pixel separation layer 351 inside the rectangular shape of the first electrode 311.
  • FIG. 13 is a vertical cross-sectional view showing the structure of the photodetector 300B according to the second variation.
  • the photodetector 300B does not have to be provided with the upper first electrode 312 and the upper pixel separation layer 352.
  • the first electrode 311 is provided extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, and can be electrically connected to the first region 310 on the bottom surface. Even with such a configuration, the photodetector 300B can suppress crosstalk between adjacent pixels by the pixel separation layer 351.
  • the photodetector 300B is not provided with the upper first electrode 312 and the upper pixel separation layer 352, so that the number of steps in the manufacturing process can be further reduced. Further, the photodetector 300B can eliminate the interface that can be a source of dark current by eliminating the interface between the upper pixel separation layer 352 and the first region 310 or the third region 330, so that dark noise can be eliminated. It can be reduced.
  • FIG. 14A is a vertical cross-sectional view showing the structure of the photodetector 300C according to the third variation.
  • FIG. 14B is a plan view of the photodetector 300C according to the third variation as viewed from the second surface side.
  • the control gate 361C may be provided in a vertical gate structure. Specifically, the control gate 361C may be provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate. Further, a gate insulating film 362C is provided on the side surface and the bottom surface of the control gate 361C embedded in the semiconductor substrate, and a second conductive type (for example, P type) impurity region 363 is provided around the control gate 361C. May be good. In such a case, as shown in FIG.
  • control gate 361C is provided so as to surround the periphery of the second region 320 in the in-plane direction of the semiconductor substrate, and further, the second control gate 361C is provided so as to surround the periphery of the control gate 361C.
  • a conductive type (for example, P type) impurity region 363 will be provided.
  • the photodetector 300C can further improve the controllability of the potential barrier generated in the region adjacent to the second region 320, and thus can further improve the detection characteristics of the incident light. it can.
  • FIG. 15 is a vertical cross-sectional view showing the structure of the photodetector 300D according to the fourth variation.
  • control gate 361D may be provided with a vertical gate structure. Further, the electrode 364 may be electrically connected to the impurity region 363. The electrode 364 can control the potential of the impurity region 363 by the applied voltage Vpin.
  • the photodetector 300D can make the effect of pinning in the second region 320 stronger by controlling the voltage Vpin applied to the impurity region 363 to be negative. Therefore, the photodetector 300D can further improve the detection characteristics of the incident light.
  • FIG. 16 is a vertical cross-sectional view showing the structure of the photodetector 300E according to the fifth variation.
  • the formation depth of the semiconductor substrate in the second region 320, the control gate 361E, the gate insulating film 362E, and the impurity region 363 in the thickness direction may be different for each pixel. According to this, since the photodetector 300E can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
  • the photodetector 300E can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
  • FIG. 17A is a vertical cross-sectional view showing the structure of the photodetector 300F according to the sixth variation.
  • FIG. 17B is a plan view of the photodetector 300F according to the sixth variation as viewed from the second surface side.
  • control gate 361F may be provided in a vertical gate structure, penetrates the second region 320, and is embedded in the semiconductor substrate via the gate insulating film 362F.
  • the second region 320 is provided in a circular shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351 in the in-plane direction of the semiconductor substrate, and is controlled.
  • the gate 361F may be provided so as to penetrate the center of the second region 320.
  • the photodetector 300F can further improve the controllability of the potential barrier generated in the region adjacent to the second region 320, so that the detection characteristics of the incident light can be further improved. it can.
  • FIG. 18 is a vertical cross-sectional view showing the structure of the photodetector 300G according to the seventh variation.
  • the control gate 361G may be provided in a vertical gate structure, penetrates the second region 320, and is embedded in the semiconductor substrate via the gate insulating film 362G. Further, the formation depth of the second region 320, the control gate 361G, and the gate insulating film 362G in the thickness direction of the semiconductor substrate may be different for each pixel. According to this, since the photodetector 300G can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
  • the photodetector 300G can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
  • FIG. 19 is a vertical cross-sectional view showing the structure of the photodetector 300H according to the eighth variation.
  • the formation depth of the semiconductor substrate in the first region 310 in the thickness direction may be different for each pixel. According to this, since the photodetector 300H can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
  • the photodetector 300H can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
  • FIG. 20 is a vertical cross-sectional view showing the structure of the photodetector 300I according to the ninth variation.
  • a multilayer wiring layer 370 bonded to the circuit board 380 including the circuit unit 381 is further provided on the second surface (that is, the surface opposite to the back surface) of the photodetector 300I. May be good.
  • the multilayer wiring layer 370 includes wiring and vias, and uses an electrode bonding structure 383 (also referred to as a CuCu bonding structure) to electrically connect the wiring and vias and an electrode exposed to the insulating layer 382 of the circuit board 380. Connect to.
  • the photodetector 300I can stack the circuit board 380 including the circuit unit 381 in the thickness direction of the semiconductor substrate, so that the chip area can be further reduced.
  • FIG. 21A is a vertical cross-sectional view showing the structure of the photodetector 300J according to the tenth variation.
  • 21B is a plan view of the AA cut surface of FIG. 21A.
  • a multilayer wiring layer 370 bonded to a circuit board 380 including a circuit unit 381 is further provided on the second surface (that is, the surface opposite to the back surface) of the photodetector 300J. May be good.
  • the electrode bonding structure 383J (also referred to as CuCu bonding structure) that electrically connects the wiring and vias of the multilayer wiring layer 370 and the electrodes exposed on the insulating layer 382 of the circuit board 380 is the first electrode. It may be provided so as to spread over the entire pixel region defined by the 311 and the pixel separation layer 351. According to this, the electrode bonding structure 383J can improve the photoelectric conversion efficiency in the third region 330 by reflecting the light that has passed through the third region 330 and entered the multilayer wiring layer 370 side. Specifically, as shown in FIG. 21B, the electrode bonding structure 383J divides the electrodes or wirings so that the vias 371 and 372 connected to different electrodes are electrically separated from each other, and the pixels. It may be provided so as to spread over the entire surface of the.
  • the photodetector 300J can improve the photoelectric conversion efficiency in the third region 330, so that the detection sensitivity of the incident light can be improved.
  • FIG. 22A is a vertical cross-sectional view showing the structure of the photodetector 300K according to the eleventh variation.
  • FIG. 22B is a plan view of the B-BB cut surface of FIG. 22A.
  • a multilayer wiring layer 370 bonded to the circuit board 380 including the circuit unit 381 is further provided. May be good.
  • the wiring 373 included in the multilayer wiring layer 370 may be provided so as to spread over the entire pixel region defined by the first electrode 311 and the pixel separation layer 351. According to this, the wiring 373 can improve the photoelectric conversion efficiency in the third region 330 by reflecting the light that has passed through the third region 330 and entered the multilayer wiring layer 370 side.
  • the wiring 373 electrically connected to the control gate 361 may be provided so as to extend over the entire surface of the pixel so as to surround the periphery of the second electrode 321.
  • the photodetector 300K can improve the photoelectric conversion efficiency in the third region 330, so that the detection sensitivity of the incident light can be improved.
  • FIG. 23 is a vertical cross-sectional view showing the structure of the photodetector 300L according to the twelfth variation.
  • a scattering structure 355L may be further provided on the first surface (that is, the back surface which is the incident surface of light) of the photodetector 300L.
  • the scattering structure 355L is a concavo-convex structure provided with a repeating period equal to or less than the wavelength of the incident light, and is, for example, a moth-eye structure.
  • the scattering structure 355L can reduce the possibility that the incident light passes through the third region 330 by scattering the light incident on the photodetector 300L.
  • the scattering structure 355L may be formed by processing the first surface of the semiconductor substrate, or may be formed by laminating a concavo-convex structure on the first surface of the semiconductor substrate.
  • the photodetector 300L can improve the photoelectric conversion efficiency in the third region 330 by scattering the incident light. Therefore, the photodetector 300L can improve the detection sensitivity of the incident light.
  • FIG. 24A is a vertical cross-sectional view showing the structure of the photodetector 300M according to the thirteenth variation.
  • FIG. 24B is a plan view of the C-CC cut plane of FIG. 24A.
  • a diffraction grating structure 355M may be further provided on the first surface (that is, the back surface which is the incident surface of light) of the photodetector 300M.
  • the diffraction grating structure 355M may have a structure in which a plurality of concentric irregularities are formed at intervals according to the wavelength of the incident light.
  • the diffraction grating structure 355M can collect the incident light at a predetermined position in the pixel by branching the light incident on the photodetector 300M into a plurality of paths.
  • the photodetector 300M can improve the photoelectric conversion efficiency in the third region 330 by condensing the incident light at a predetermined position. Therefore, the photodetector 300M can improve the detection sensitivity of the incident light.
  • FIG. 25 is a vertical cross-sectional view showing the structure of the photodetector 300N according to the 14th variation.
  • the first region 310 is electrically connected to the first surface electrode 313N provided on the first surface of the semiconductor substrate via the first surface insulating layer 353.
  • the first surface electrode 313N functions as a cathode electrode.
  • the first surface electrode 313N is, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided at.
  • the first electrode 311 is not electrically connected to the first region 310, but is electrically connected to the second conductive type second conductive type region 363N provided inside the third region 330. ..
  • the first electrode 311 can control the potential of the third region 330 via the second conductive type region 363N. Therefore, the first electrode 311 can function as an electrode for controlling the potential barrier generated in the third region 330.
  • the photodetector 300N can further improve the controllability of the potential barrier generated in the third region 330, so that the detection characteristics of the incident light can be further improved.
  • FIG. 26 is a vertical cross-sectional view showing the structure of the photodetector 300O according to the fifteenth variation.
  • a second conductive type (for example, P type) first region 310O is provided on the first surface side of the semiconductor substrate, and a second surface opposite to the first surface is provided.
  • a first conductive type (for example, N type) second region 320O is provided on the side.
  • the first electrode 311 electrically connected to the first region 310O functions as an anode electrode
  • the second electrode 321 electrically connected to the second region 320O functions as a cathode electrode. It will be. Even with such a configuration, the photodetector 300O can detect the incident light for each pixel.
  • the photodetector 300O can exchange the polarity of the conductive region, so that the degree of freedom in structural design can be improved.
  • FIG. 27 is a vertical cross-sectional view illustrating the formation depth of the second region 320 and the first electrode 311.
  • the formation depth of the second region 320 from the second surface of the semiconductor substrate is h_P +, and the formation depth from the second surface of the semiconductor substrate to the bottom surface of the first electrode 311 is h_D.
  • h_F be the formation depth from the second surface of the semiconductor substrate to the bottom surface of the upper first electrode 312 (that is, the distance from the second surface to the first surface of the semiconductor substrate).
  • h_D has the following relationship with h_P + and h_F. h_P + ⁇ h_D ⁇ h_F
  • the photodetector 300 can suppress the DCR (Dark Count Rate). If the formation depth h_D of the first electrode 311 is excessively large, the process accuracy of the manufacturing process may be lowered, and the manufacturing yield may be lowered. Therefore, it is desirable that the formation depth h_D of the first electrode 311 is set larger within a range in which the desired process accuracy can be maintained.
  • FIG. 28 is a timing chart showing an example of the operation of the ToF sensor of the photodetector 300 according to the present embodiment.
  • FIG. 29 is an explanatory diagram illustrating a light source used in the ToF sensor.
  • FIG. 30A is a vertical cross-sectional view illustrating the state of the photodetector 300 at the timing of FIG. 28 (1)
  • FIG. 30B describes the state of the photodetector 300 at the timing of FIG. 28 (2).
  • It is a vertical cross-sectional view
  • FIG. 30C is a vertical cross-sectional view illustrating a state of the photodetector 300 at the timing of FIG. 28 (3).
  • a positive voltage is applied to the voltage VSW applied to the gate of the switch transistor to turn on the switch transistor.
  • the voltage Va applied to the second electrode 321 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 310 and the second region 320 of the photodetector 300.
  • the voltage Vg applied to the control gate 361 is set to a negative voltage (for example, -1V).
  • a pulsed negative voltage V light is applied to the light source LD such as a laser diode or an LED (Light Emitting Diode) at the timing of (2) in FIG. 28.
  • the object is irradiated with pulsed light.
  • the voltage Va applied to the second electrode 321 to a positive voltage (for example, + 1V)
  • a forward bias is applied between the first region 310 and the second region 320 of the photodetector 300.
  • the voltage Vg applied to the control gate 361 is set to a positive voltage (for example, + 1V).
  • the photodetector 300 can calculate the distance to the object by calculating the difference between the light emission timing t2 of the light source LD and the light detection delay time t1.
  • the voltage Va applied to the second electrode 321 at the timing of (3) in FIG. 28 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 310 and the second region 320 of the photodetector 300, so that the state of the photodetector 300 is reset.
  • the voltage Vg applied to the control gate 361 may also be set to a negative voltage (for example, -1V).
  • the photodetector 300 can detect the distance to the object for each frame.
  • FIG. 31A is a vertical cross-sectional view showing the structure of the photodetector 300P according to the first modification.
  • FIG. 31B is a plan view of the photodetector 300P according to the first modification as viewed from the second surface side.
  • FIG. 32 is a timing chart showing an example of a drive voltage in the photodetector 300P according to the first modification.
  • a potential control region 365 is provided on the second surface side of the semiconductor substrate instead of the control gate 361 and the gate insulating film 362.
  • the photodetector 300P can control a potential barrier generated in a region adjacent to the second region 320 by applying a voltage to the potential control region 365.
  • the potential control region 365 is a first conductive type region (for example, N + layer), and is provided so as to surround the second region 320 with the insulating layer 366 interposed therebetween. That is, as shown in FIG. 31B, on the second surface side of the semiconductor substrate, the second region 320 is provided in an island shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351. Further, an insulating layer 366 is provided so as to surround the periphery of the second region 320, and a potential control region 365 is provided so as to surround the periphery of the insulating layer 366.
  • the photodetector 300P detects the incident light by controlling the voltage Vg applied to the potential control region 365 in the same manner as the control gate 361. Can be done.
  • FIG. 33A is a plan view seen from the second surface side showing the structure of the photodetector 300Q according to the second modification.
  • FIG. 33B is a vertical cross-sectional view showing the structure of the photodetector 300Q on the AA cut surface of FIG. 33A.
  • FIG. 33C is a vertical cross-sectional view showing the structure of the photodetector 300Q on the B-BB cut surface of FIG. 33A.
  • the photodetector 300Q according to the second modification further includes a transfer gate and a floating diffusion with respect to the photodetector 300P according to the first modification, and is general. The difference is that it can also function as a photodiode (PD).
  • PD photodiode
  • the photodetector 300Q has a first region 310, a third region 330, and a second region 320, similarly to the photodetector 300P according to the first modification.
  • the insulating layer 366, the potential control region 365, and the electrode 367 that applies a voltage to the potential control region 365 are provided.
  • the photodetector 300Q can function as a DPD sensor in the first direction (vertical direction in FIG. 33A) in the plane of the semiconductor substrate.
  • the photodetector 300Q has a first region 310, a third region 330, a second region 320, a first conductive region 391, a transfer gate TRG, and a floating second conductive type. It includes a diffusion FD and an extraction electrode 393. As a result, the photodetector 300Q can function as a normal PD in the second direction (lateral direction in FIG. 33A) orthogonal to the first direction in the plane of the semiconductor substrate.
  • the pixel transistors constituting the pixel circuit may be provided, for example, in the pixel transistor region Tr provided adjacent to the pixel separation layer 351.
  • a reset transistor, an amplifier transistor, a selection transistor, or a switch transistor constituting a pixel circuit may be provided in the pixel transistor region Tr.
  • Each of the transistors provided in the pixel transistor region Tr may be electrically insulated from each other by, for example, an insulating layer provided by digging a semiconductor substrate.
  • the photodetector 300Q according to the second modification may include, for example, a pixel circuit showing an equivalent circuit in FIG. 34.
  • FIG. 34 is a circuit diagram showing an example of an equivalent circuit of a pixel circuit included in the DPD sensor and the photodetector 300Q that functions as a PD.
  • DPD / PD indicates a photoelectric conversion unit having a PIN diode structure in which the above-mentioned first region 310, third region 330, and second region 320 are laminated.
  • the photoelectric conversion unit DPD is electrically connected to the power supply Va via the switch transistor SW. Further, as a pixel circuit on the PD side, the photoelectric conversion unit PD is electrically connected to the floating diffusion FD via the transfer transistor TRG.
  • the power supply Vd is further connected to the floating diffusion FD via the reset transistor RST, and the gate of the amplifier transistor AMP is also connected.
  • the drain of the amplifier transistor AMP is connected to the power supply Vd, and the source of the amplifier transistor AMP is connected to the external output Output via the selection transistor SEL.
  • the power supply Va on the DPD sensor side and the power supply Vd on the PD side may be different power supplies or the same power supply.
  • Second embodiment (Basic structure) Next, with reference to FIGS. 35 to 38, the basic structure of the photodetector according to the second embodiment of the present disclosure will be described.
  • the photodetector according to the present embodiment detects incident light by measuring the delay time until a forward current flows when the applied bias is reversed from a reverse bias to a forward bias, that is, a so-called DPD. It is a sensor.
  • FIG. 35 is a schematic diagram showing the movement of electric charges after reversing the bias applied to the photodetector from the reverse bias to the forward bias in chronological order.
  • FIG. 36 is a graph showing changes in the band structure in chronological order after the bias applied to the photodetector is reversed from the reverse bias to the forward bias.
  • the photodetector when the bias applied to the photodetector is reversed from the reverse bias to the forward bias, the photodetector first starts with the cathode electrode (first electrode) to the P + layer. Electrons e flow toward the dip (also called a dip) of the band structure around the (second region).
  • the outflow of holes h from the P + layer (second region) lowers the potential barrier around the N + layer (first region), so that N +
  • the flow of electrons e from the layer (first region) to the periphery of the P + layer (second region) is further increased.
  • the outflow of holes h from the P + layer (second region) and the outflow of electrons e from the N + layer (first region) increase, so that the N + layer (first region) and the P + layer (first region) are increased.
  • the potential barriers around the two regions) decrease with each other.
  • the time from inversion from reverse bias to forward bias to reaching a steady state by the above behavior changes depending on the intensity of incident light. This is because the electrons generated by the photoelectric conversion of the incident light accelerate the inflow of the electrons e from the cathode electrode (first electrode) to the dip around the P + layer (second region). Therefore, the photodetector according to the present embodiment can detect incident light by measuring the delay time until the forward current flows when the applied bias is reversed from the reverse bias to the forward bias. it can.
  • FIG. 37 is a vertical sectional view showing the basic structure of the photodetector 400 according to the present embodiment
  • FIG. 38 is a transmission plane from the first surface side showing the basic structure of the photodetector 400 according to the present embodiment. It is a figure.
  • the photodetector 400 includes, for example, a first region 410, a second region 420, a third region 430, a first electrode 411, a via 412, and a first surface insulating layer 451.
  • Pixel separation layer 450 through insulating layer 452, third electrode 471, potential control region 473, fourth electrode 472, reset region 474, second electrode 421, control gate 461, and gate insulating film. It is equipped with 462.
  • the first region 410 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 420 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the third region 430 is a third conductive type region (for example, layer i) provided between the first region 410 and the second region 420 of a semiconductor substrate such as silicon (Si).
  • the first electrode 411 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 451 and is electrically connected to the first region 410 via the via 412 or the like penetrating the first surface insulating layer 451. Connecting.
  • the first electrode 411 functions as, for example, a cathode electrode.
  • the first electrode 411 is provided, for example, so as to straddle the through insulating layer 452 provided at the boundary between pixels, and is electrically connected to the first region 410 of each pixel by a via 412 provided for each pixel. Will be done. That is, the first electrode 411 is a common electrode that supplies a common potential to the first region 410 of each pixel.
  • the third electrode 471 and the fourth electrode 472 are provided extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate at the boundary of each pixel, and are wider than the third electrode 471 and the fourth electrode 472. It abuts on the bottom surface with a small penetrating insulating layer 452.
  • the third electrode 471 and the fourth electrode 472 may be provided so as to face each other along the boundary of the pixel region.
  • the through insulating layer 452 has a width smaller than that of the third electrode 471 and the fourth electrode 472, and extends from the bottom surface of the third electrode 471 and the fourth electrode 472 to the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate. It is provided.
  • the pixel separation layer 450 is provided on each side surface of the third electrode 471 and the fourth electrode 472.
  • the pixel separation layer 450 is provided with a through-insulation layer 452 provided above the third electrode 471 and the fourth electrode 472, and the photodetector 400 for each pixel provided adjacent to the semiconductor substrate in the in-plane direction. Each of them can be electrically separated from each other.
  • the width of the third electrode 471 and the fourth electrode 472 is larger than the width of the through insulating layer 452, a part of the bottom surface of the third electrode 471 and the fourth electrode 472 that comes into contact with the through insulating layer 452 is formed. It is not covered by the through insulating layer 452 and is exposed on the third region 430 side. Therefore, the third electrode 471 can be electrically connected to the potential control region 473 provided inside the third region 430 at a part of the bottom surface exposed to the third region 430 side. Further, the fourth electrode 472 can be electrically connected to the reset region 474 provided inside the third region 430 at a part of the bottom surface exposed to the third region 430 side.
  • the potential control region 473 is a second conductive type region and is provided so as to be electrically connected to the third electrode 471.
  • the potential control region 473 can control the potential of the third region 430 by applying a negative voltage from the third electrode 471.
  • the third electrode 471 and the potential control region 473 can control the size of the potential barrier generated in the third region 430.
  • the reset region 474 is a first conductive type region and is provided so as to be electrically connected to the fourth electrode 472.
  • the electric charge remaining inside the third region 430 can be discharged.
  • the fourth electrode 472 and the reset region 474 more reliably discharge the electric charge remaining inside the third region 430 when the detection of the incident light is completed by the photodetector 400, for example, and the photodetection It is possible to suppress the generation of afterimages in the device 400.
  • the potential control region 473 and the reset region 474 may be provided in the planar arrangement shown in FIG. 38.
  • the potential control region 473 may be provided along one side of the rectangular pixel region
  • the reset region 474 may be provided along the other side facing one side of the rectangular pixel region. Good.
  • the second electrode 421 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 420.
  • the second electrode 421 functions as, for example, an anode electrode and is electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
  • the control gate 461 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 462.
  • the control gate 461 is provided to control the potential barrier in the third region 430 by applying a voltage.
  • the first electrode 411, the second electrode 421, the third electrode 471, the fourth electrode 472, the via 412, and the control gate 461 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti). , Or a metal such as tantalum (Ta), polysilicon (poly-Si), or other conductive material.
  • the pixel separation layer 450, the through insulating layer 452, the first surface insulating layer 451 and the gate insulating film 462 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or so-called low-k. It may be provided by an insulator such as a material.
  • the photodetector 400 is provided as a back surface (that is, the first surface) irradiation type CMOS (Complementary MOS) image sensor, thereby reducing the wiring on the back surface side which is the light incident surface and reducing the wiring on the back surface side.
  • the aperture ratio of the can be increased.
  • the photodetector 400 uses the third electrode 471 that controls the potential of the third region 430 and the fourth electrode 472 that discharges charges from the third region 430 from the second surface of the semiconductor substrate to the semiconductor substrate. It can be provided so as to extend in the thickness direction.
  • the light detection device 400 is a light incident surface even when the third electrode 471 that controls the potential of the third region 430 and the fourth electrode 472 that discharges the electric charge from the third region 430 are provided. It is possible to reduce the wiring provided on the back surface side and prevent the pixel area from increasing.
  • FIG. 39 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400A according to the first variation.
  • FIG. 39 shows only the configuration of interest in the configuration of the photodetector 400A.
  • the third electrode 471 and the potential control region 473 are provided along one side of the rectangular pixel region, and the fourth electrode 472 and the reset region 474 are one of the rectangular pixel regions. It may be provided along the other side facing the side of.
  • Each of the third electrode 471 and the fourth electrode 472 may be provided independently for each pixel.
  • the third electrode 471 of each pixel may be electrically connected to each other by a wiring provided on the second surface side extending in the extending direction of the third electrode 471.
  • the fourth electrode 472 of each pixel may be electrically connected to each other by a wiring provided on the second surface side extending in the extending direction of the fourth electrode 472.
  • the wiring that electrically connects the third electrode 471 of each pixel and the wiring that electrically connects the fourth electrode 472 of each pixel may be provided so as to extend in the same direction so as not to intersect with each other.
  • the photodetector 400A can electrically connect the third electrode 471 or the fourth electrode 472 of each pixel with a simpler wiring structure. Therefore, the photodetector 400A can further simplify the manufacturing process.
  • FIG. 40 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400B according to the second variation.
  • FIG. 40 shows only the configuration of interest among the configurations of the photodetector 400B.
  • the third electrode 471 and the potential control region 473 are provided along one side of the rectangular pixel region, and the fourth electrode 472 and the reset region 474 are one of the rectangular pixel regions. It may be provided along the other side facing the side of.
  • Each of the third electrode 471 and the fourth electrode 472 may be continuously provided between the pixels.
  • the third electrode 471 may be provided so as to extend in the extending direction of the potential control region 473 and may be electrically connected to the potential control region 473 of each pixel. Further, the third electrode 471 may be electrically connected to each other in a direction orthogonal to the extending direction of the third electrode 471 by a wiring provided at the end of the pixel array.
  • the fourth electrode 472 may be provided so as to extend in the extending direction of the reset region 474 and may be electrically connected to the reset region 474 of each pixel. Further, the fourth electrode 472 may be electrically connected to each other in a direction orthogonal to the extending direction of the fourth electrode 472 by wiring provided at the end of the pixel array.
  • the photodetector 400B can electrically connect the third electrode 471 or the fourth electrode 472 of each pixel with a wiring structure in which the capacitance between the wirings is smaller. Therefore, the photodetector 400B can reduce the noise caused by the capacitance between the wirings.
  • FIG. 41 is a vertical cross-sectional view showing the structure of the photodetector 400C according to the third variation.
  • a second conductive type fifth region 480 may be provided on the inner side of the semiconductor substrate with respect to the first region 410.
  • the fifth region 480 is provided on the inner side of the semiconductor substrate with respect to the first region 410, and is a second conductive type region (for example,) having a lower impurity concentration than the second region 420 or the potential control region 473 (for example). P-layer).
  • the fifth region 480 can reduce DCR (Dark Count Rate) and reduce dark noise by suppressing the flow of electrons from the first region 410.
  • the fifth region 480 also suppresses the electric charge remaining inside the third region 430 from being discharged from the first region 410 when the detection of the incident light is completed by the photodetector 400B.
  • the photodetector 400C separately includes a reset region 474 and a fourth electrode 472 capable of discharging the electric charge remaining inside the third region 430 to the outside, the electron by providing the fifth region 480 is provided. It is possible to avoid the influence of the decrease in discharge.
  • the photodetector 400C can reduce DCR (Dark Count Rate) and reduce dark noise without lowering the emission of electrons from the third region 430.
  • FIG. 42 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400D according to the fourth variation.
  • FIG. 42 shows only the configuration of interest in the configuration of the photodetector 400D.
  • 43A is a vertical cross-sectional view showing the configuration of the photodetector 400D on the AA cut surface of FIG. 42
  • FIG. 43B is a vertical cross section showing the configuration of the photodetector 400D on the B-BB cut surface of FIG. 42. It is a figure.
  • the photodetector 400D according to the fourth variation is different from the photodetector 400B according to the second variation in that a through electrode 475 is provided.
  • the configuration of the photodetector 400D on the AA cut surface is substantially the same as the configuration of the photodetector 400 according to the basic structure described with reference to FIG. 37. ..
  • through electrodes 475 are provided on the sides where the third electrode 471, the potential control region 473, the fourth electrode 472, and the reset region 474 are not provided in the rectangular pixel region. Be done.
  • the through electrode 475 is provided inside the pixel separation layer 450 so as to penetrate the semiconductor substrate from the second surface to the first surface, and is electrically connected to the first electrode 411 provided on the first surface side of the semiconductor substrate. To do.
  • the through electrode 475 makes it possible to form a wiring for electrically connecting the first electrodes 411 of each pixel to each other on the second surface side of the semiconductor substrate.
  • the through silicon via 475 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the wiring electrically connected to the through electrode 475 and electrically connected to the first electrode 411 of each pixel is orthogonal to the extending direction of the third electrode 471 and the fourth electrode 472 in the plane of the semiconductor substrate. It may be provided so as to extend in the direction of Since the third electrode 471 and the fourth electrode 472 are provided inside the semiconductor substrate, the wiring electrically connected to the through electrode 475 can be arranged without interfering with the third electrode 471 and the fourth electrode 472. ..
  • the photodetector 400D can reduce the wiring formed on the first surface side which is the incident surface of the light, so that the aperture ratio of the incident surface of the light can be improved. ..
  • the photodetector according to the present embodiment detects incident light by measuring the delay time until a forward current flows when the applied bias is reversed from a reverse bias to a forward bias, that is, a so-called DPD. It is a sensor.
  • FIG. 44 is a schematic diagram showing the movement of electric charges after reversing the bias applied to the photodetector from the reverse bias to the forward bias in chronological order.
  • FIG. 45 is a graph showing changes in the energy band structure in time series after reversing the bias applied to the photodetector from the reverse bias to the forward bias.
  • the light detection device when the bias applied to the light detection device is reversed from the reverse bias to the forward bias, the light detection device first starts with the cathode electrode (first electrode) to the P + layer. Electrons e flow toward the dip (also called dip) of the energy band structure around (the second region).
  • the outflow of holes h from the P + layer (second region) lowers the potential barrier around the N + layer (first region), so that N +
  • the flow of electrons e from the layer (first region) to the periphery of the P + layer (second region) is further increased.
  • the outflow of holes h from the P + layer (second region) and the outflow of electrons e from the N + layer (first region) increase, so that the N + layer (first region) and the P + layer (first region) are increased.
  • the potential barriers around the two regions) decrease with each other.
  • the time from inversion from reverse bias to forward bias to reaching a steady state by the above behavior changes depending on the intensity of incident light. This is because the electrons generated by the photoelectric conversion of the incident light accelerate the inflow of the electrons e from the cathode electrode (first electrode) to the dip around the P + layer (second region). Therefore, the photodetector according to the present embodiment can detect incident light by measuring the delay time until the forward current flows when the applied bias is reversed from the reverse bias to the forward bias. it can.
  • FIG. 46 is a vertical cross-sectional view showing the basic structure of the photodetector 500 according to the present embodiment.
  • the photodetector 500 is insulated from the first region 510, the second region 520, the third region 530, the first electrode 511, the second electrode 521, and the fourth region 525. It includes a layer 570.
  • the first region 510 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the first region 510 may be provided, for example, on the first surface side of the semiconductor substrate so as to spread over the entire surface.
  • the second region 520 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the second region 520 may be provided in an island shape on the second surface side of the semiconductor substrate, for example.
  • the third region 530 is a third conductive type region (for example, i-layer) provided between the first region 510 and the second region 520 of a semiconductor substrate such as silicon (Si).
  • a third conductive type region for example, i-layer
  • the first electrode 511 is provided on the first surface of the semiconductor substrate and is electrically connected to the first region 510.
  • the first electrode 511 functions as, for example, a cathode electrode.
  • the first electrode 511 may be a common electrode that is spread over a plurality of pixels on the first surface of the semiconductor substrate and supplies a common potential to each first region 510 of the pixels.
  • the second electrode 521 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 520.
  • the second electrode 521 functions as, for example, an anode electrode.
  • the first electrode 511 and the second electrode 521 are, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), and polysilicon (poly-Si). , Or other conductive material.
  • a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), and polysilicon (poly-Si). , Or other conductive material.
  • the fourth region 525 is a first conductive type region (for example, N layer) provided in contact with the second region 520 in the depth direction of the semiconductor substrate.
  • the fourth region 525 may be a first conductive type region provided inside the semiconductor substrate immediately below the second region 520 and having a lower impurity concentration than the first region 510.
  • the insulating layer 570 surrounds the second region 520 in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520 in the thickness direction of the semiconductor substrate.
  • the insulating layer 570 may be provided over the entire second surface of the semiconductor substrate including the periphery of the second region 520, or may be provided only in the region around the second region 520 provided in an island shape. You may.
  • the insulating layer 570 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the photodetector 500 can be used, for example, for a photon counting application for measuring the number of incident photons.
  • the photodetector 500 changes from the state shown in (1) to (2) in the state transition described with reference to FIGS. 44 and 45.
  • one electron ie, one photon
  • the photodetector 500 can further increase the modulation force per electron (that is, the degree of influence) on the potential barrier by reducing the capacitance of the potential barrier generated adjacent to the second region 520. It becomes important.
  • the second region 520 is formed in a small island-shaped area, so that the size of the capacitance generated in the second region 520 is further reduced, and the second region 520 is formed.
  • the area where the capacitance is generated can be limited to the lower part of the second area 520.
  • the photodetector 500 can generate a potential barrier due to the built-in potential by providing the fourth region 525 of the first conductive type below the second region 520 of the second conductive type.
  • the photodetector 500 has a potential barrier due to the built-in potential, and the capacity of the potential barrier generated in the region adjacent to the second region 520 becomes small, so that the photodetector 500 can operate with a smaller number of electrons. It will be possible.
  • FIG. 47 is a vertical cross-sectional view showing the structure of the photodetector 500A according to the first variation.
  • the first region 510 and the first electrode 511 may be provided on the second surface side of the semiconductor substrate (that is, the surface side where the second region 520 and the second electrode 521 are provided). ..
  • an in-plane separation layer 552 is further provided between the first region 510 and the second region 520 provided on the same surface side in addition to the insulating layer 570 surrounding the periphery of the second region 520. You may.
  • the in-plane separation layer 552 is provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
  • the in-plane separation layer 552 may be formed to a region deeper than the formation depth of the first region 510 and the second region 520.
  • the photodetector 500A the first region 510, the first electrode 511, the second region 520, and the second electrode 521 are provided on the same surface side of the semiconductor substrate, so that the manufacturing process can be performed. It can be simplified. Therefore, the photodetector 500A can reduce the process difficulty of the manufacturing process.
  • FIG. 48 is a vertical cross-sectional view showing the structure of the photodetector 500B according to the second variation.
  • the photodetector 500B is different from the photodetector 500A according to the first variation in that the insulating layer 570 is provided so as to spread over the entire second surface of the semiconductor substrate.
  • the insulating layer 570 may be provided in a region other than the region where the first region 510 and the second region 520 are provided on the second surface of the semiconductor substrate.
  • the photodetector 500B can improve the charge collection efficiency of the first region 510 and the second region 520.
  • FIG. 49 is a vertical cross-sectional view showing the structure of the photodetector 500C according to the third variation.
  • the photodetector 500C is different from the photodetector 500B according to the second variation in that the fourth region 525C is provided on the semiconductor substrate below the insulating layer 570.
  • the fourth region 525C may be provided to a region deeper than the formation depth of the insulating layer 570, and may be provided so as to extend to the inside of the semiconductor substrate below the insulating layer 570.
  • the photodetector 500C can improve the charge collection efficiency of the first region 510 and the second region 520.
  • FIG. 50 is a vertical cross-sectional view showing the structure of the photodetector 500D according to the fourth variation.
  • the photodetector 500D differs from the photodetector 500C according to the third variation in that the polarities of the conductive type in each region are interchanged.
  • the first region 510D is a second conductive type region (for example, P + layer), and is provided on the second surface side of the semiconductor substrate at a distance from the second region 520D.
  • the second region 520D is a first conductive type region (for example, N + layer), and is provided in an island shape on the second surface side of the semiconductor substrate.
  • the fourth region 525D is a second conductive type region (for example, P layer), and is provided in contact with the second region 520D in the depth direction of the semiconductor substrate.
  • the fourth region 525D may be provided inside the semiconductor substrate directly below the second region 520D so as to extend below the insulating layer 570.
  • the first electrode 511 is provided on the second surface of the semiconductor substrate and is electrically connected to the first region 510D.
  • the first electrode 511 functions as, for example, a cathode electrode.
  • the second electrode 521 is provided on the second surface of the semiconductor substrate and is electrically connected to the second region 520D.
  • the second electrode 521 functions as, for example, an anode electrode.
  • the insulating layer 570 surrounds the second region 520D in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520D in the thickness direction of the semiconductor substrate.
  • the photodetector 500D can operate with the movement of holes instead of electrons when the applied bias is reversed from the reverse bias to the forward bias.
  • FIG. 51 is a vertical cross-sectional view showing the structure of the photodetector 500E according to the fifth variation.
  • the photodetector 500E is different from the photodetector 500C according to the third variation in that the first region 510 is provided on the first surface side of the semiconductor substrate.
  • the first region 510 is a first conductive type region (for example, N + layer), and is provided so as to spread over the entire surface on the first surface side of the semiconductor substrate.
  • the second region 520 is a second conductive type region (for example, P + layer), and is provided in an island shape on the second surface side opposite to the first surface of the semiconductor substrate.
  • the fourth region 525 is a first conductive type region (for example, N layer), and is provided in contact with the second region 520 and extends below the insulating layer 570 in the depth direction of the semiconductor substrate.
  • the first electrode 511 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 551, and is electrically connected to the first region 510 via a via 512 or the like penetrating the first surface insulating layer 551.
  • the second electrode 521 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 520.
  • the insulating layer 570 surrounds the second region 520 in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520 in the thickness direction of the semiconductor substrate.
  • the photodetector 500E is configured with a back surface (ie, first surface) irradiation type structure, the ratio of the number of charges generated to the incident light (that is, quantum efficiency). Can be improved.
  • FIG. 52 is a vertical cross-sectional view showing the structure of the photodetector 500F according to the sixth variation.
  • the photodetector 500F is different from the photodetector 500E according to the fifth variation in that a pixel separation layer 550 is further provided between the pixels.
  • the pixel separation layer 550 is provided so as to penetrate the semiconductor substrate in the thickness direction so as to surround the pixel region.
  • the pixel separation layer 550 can suppress crosstalk between adjacent pixels by electrically separating adjacent pixels from each other.
  • the pixel separation layer 550 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the photodetector 500F improves the physical or electrical separability between adjacent pixels, so that crosstalk between pixels can be suppressed.
  • 53A and 53B are plan views from the second surface side for explaining variations in the arrangement and shape of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521.
  • the second region 520 and the second electrode 521 may be provided in a rectangular shape substantially in the center of the pixel region determined to be a rectangular shape by the pixel separation layer 550.
  • the insulating layer 570 may surround the second region 520 and the second electrode 521 with a rectangular shape having rounded corners.
  • the centers of gravity of the shapes of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521 may be the same or different.
  • the second region 520 and the second electrode 521 may be provided in a circular shape or an elliptical shape substantially in the center of the pixel region determined to have a rectangular shape by the pixel separation layer 550.
  • the insulating layer 570 may surround the second region 520 and the second electrode 521 with a rectangular shape having rounded corners.
  • the centers of gravity of the shapes of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521 may be the same or different.
  • the second region 520 and the second electrode 521 eliminate the electric field concentration and can stabilize the electric field, so that the capacitance of the potential barrier generated in the region adjacent to the second region 520 is increased. It can be reduced. Further, according to such a planar shape, the second region 520 and the second electrode 521 can be miniaturized more easily.
  • FIG. 54 is a vertical cross-sectional view showing the basic structure of the photodetector 600 according to the present embodiment.
  • 55A and 55B are graphs showing the energy band structure of the photodetector 600 according to the present embodiment.
  • the photodetector 600 includes, for example, a first region 610, a second region 620, a third region 630, a fourth region 625, a fifth region 615, and a first electrode 611.
  • the via 612, the first surface insulating layer 651, the pixel separation layer 650, and the second electrode 621 are provided.
  • the first region 610 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 620 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the fourth region 625 is a first conductive type region (for example, N + layer) provided in contact with the second region 620 on the inner side of the semiconductor substrate with respect to the second region 620.
  • the fifth region 615 is a second conductive type region (for example, P + layer) provided in contact with the first region 610 on the inner side of the semiconductor substrate with respect to the first region 610.
  • the third region 630 is a third conductive type region (for example, layer i) provided between the fourth region 625 and the fifth region 615 of the semiconductor substrate.
  • the photodetector 600 is a PN / i / PN diode formed by the first region 610, the second region 620, the third region 630, the fourth region 625, and the fifth region 615.
  • the first electrode 611 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 651, and is electrically connected to the first region 610 via a via 612 or the like penetrating the first surface insulating layer 651. Connecting.
  • the first electrode 611 functions as, for example, a cathode electrode.
  • the first electrode 611 extends across the pixel separation layer 650 provided along the boundary between pixels, and is electrically connected to the first region 610 of each pixel by a via 612 provided for each pixel.
  • the pixel separation layer 650 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other.
  • the pixel separation layer 650 may be provided, for example, in a grid pattern along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
  • the second electrode 621 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 620.
  • the second electrode 621 functions as, for example, an anode electrode.
  • the first electrode 611, the via 612, and the second electrode 621 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), and polysilicon (poly). -Si) or other conductive material may be provided.
  • the first surface insulating layer 651 and the pixel separation layer 650 are provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. May be good.
  • a forward current may be generated even if the photon does not reach immediately after the applied bias is inverted from the reverse bias to the forward bias.
  • a diffusion current easily flows from the cathode electrode beyond the potential barrier depending on the height of the potential barrier on the cathode electrode side that occurs when the applied bias is inverted from the reverse bias to the forward bias.
  • the dip also called a dip
  • the energy band structure on the anode electrode side becomes shallow, so that in the photodetector according to the comparative example, a forward current may be generated even if the photons do not reach. possible.
  • the photodetector 600 includes a PN / i / PN diode. Therefore, as shown in FIG. 55A, the photodetector 600 constantly sets a potential barrier of an energy band on the first electrode 611 side, which is a cathode electrode, by the built-in potential of the PN junction of the first region 610 and the fifth region 615. Can be formed into. According to this, since the photodetector 600 can suppress the movement of electrons due to the diffusion current, it is possible to suppress the generation of a forward current when there is no incident of photons. Therefore, the photodetector 600 according to the present embodiment can suppress the generation of false signals.
  • Such a photodetector 600 can operate as follows, for example.
  • FIG. 56A is a vertical cross-sectional view showing the structure of the photodetector 600A according to the first variation.
  • FIG. 56B is a plan view of the photodetector 600A according to the first variation as viewed from the second surface side.
  • the second region 620 may be provided so as to extend over substantially the entire region defined by the pixel separation layer 650, for example.
  • the first region 610, the fourth region 625, and the fifth region 615 may be provided so as to extend over substantially the entire region defined by the pixel separation layer 650 (not shown).
  • the second electrode 621 may be provided in an island shape at substantially the center of the region defined by the pixel separation layer 650, for example.
  • the photodetector 600A increases the occupied area by arranging the first region 610, the second region 620, the fourth region 625, and the fifth region 615 in the thickness direction of the semiconductor substrate. It can be made smaller. Further, the photodetector 600A can suppress crosstalk between pixels by providing the pixel separation layer 650 on the entire circumference of the pixels.
  • FIG. 57A is a vertical cross-sectional view showing the structure of the photodetector 600B according to the second variation.
  • FIG. 57B is a plan view of the photodetector 600B according to the second variation as viewed from the second surface side.
  • a control electrode 661 capable of controlling the potential of the fourth region 625 may be provided on the second surface side of the semiconductor substrate of the pixel separation layer 650.
  • the control electrode 661 controls the potential of the fourth region 625 to control the depth of the dip of the energy band structure formed on the second electrode 621 side and the amount of electric charge required to fill the dip. Can be done.
  • control electrode 661 may be provided extending from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate and may be electrically connected to the fourth region 625.
  • the control electrode 661 is provided with a side wall insulating layer 662 on the side surface and is provided so as to extend to the fourth region 625 with a width larger than that of the pixel separation layer 650, so that the control electrode 661 is electrically connected to the fourth region 625.
  • the control electrode 661 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the side wall insulating layer 662 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
  • an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
  • the photodetector 600B can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 58A is a vertical cross-sectional view showing the structure of the photodetector 600C according to the third variation.
  • FIG. 58B is a plan view of the photodetector 600C according to the third variation as viewed from the second surface side.
  • a control electrode 661C capable of controlling the potential of the fifth region 615 may be provided on the second surface side of the semiconductor substrate of the pixel separation layer 650.
  • the control electrode 661C can control the height of the potential barrier of the energy band structure formed on the first electrode 611 side by controlling the potential of the fifth region 615.
  • control electrode 661C may be provided extending from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate and may be electrically connected to the fifth region 615.
  • the control electrode 661C is provided with a side wall insulating layer 662C on the side surface and is provided so as to extend to the fifth region 615 with a width larger than the pixel separation layer 650, so that the control electrode 661C is electrically connected to the fifth region 615.
  • the control electrode 661C is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the side wall insulating layer 662C may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
  • an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
  • the photodetector 600C can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 59A is a vertical cross-sectional view showing the structure of the photodetector 600D according to the fourth variation.
  • FIG. 59B is a plan view of the photodetector 600D according to the fourth variation as viewed from the second surface side.
  • the second region 620D may be provided so as to have a smaller volume than the first region 610 by being provided in an island shape on the second surface side of the semiconductor substrate.
  • the fourth region 625D may be provided so as to cover the side surface and the bottom surface of the second region 620D. That is, in the photodetector 600D, the area of the PN junction on the second electrode 621 side by the second region 620D and the fourth region 625D is the area of the PN junction on the first electrode 611 side by the first region 610 and the fifth region 615. It may be provided so as to be smaller than.
  • the photodetector 600D fills the dip of the energy band structure formed on the second electrode 621 side by reducing the capacitance generated in the region adjacent to the second region 620D on the second electrode 621 side.
  • the amount of charge required for this can be controlled. Therefore, the photodetector 600D can operate with a smaller number of photoelectrons.
  • the photodetector 600D can further improve the detection characteristics of incident light.
  • FIG. 60 is a vertical cross-sectional view showing the structure of the photodetector 600E according to the fifth variation.
  • the photodetector 600E is different from the photodetector 600D according to the fourth variation in that the control electrode 663 is further electrically connected to the fourth region 625E.
  • the control electrode 663 may be provided on the second surface of the semiconductor substrate and electrically connected to the fourth region 625E.
  • the control electrode 663 controls the depth of the dip of the energy band structure formed on the second electrode 621 side and the amount of electric charge required to fill the dip. Can be done.
  • the control electrode 663 is provided of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. You may.
  • the photodetector 600E can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 61A is a vertical cross-sectional view showing the structure of the photodetector 600F according to the sixth variation.
  • FIG. 61B is a plan view of the photodetector 600F according to the sixth variation as viewed from the second surface side.
  • the photodetector 600F is different from the photodetector 600D according to the fourth variation in that a control gate 664 is further provided on the fourth region 625F.
  • the control gate 664 may be provided on the fourth region 625F with a gate insulating film 665 in a planar shape surrounding the circumference of the second region 620F.
  • the control gate 664 controls the potential of the fourth region 625F by applying a voltage, so that the depth of the dip of the energy band structure formed on the second electrode 621 side and the electric charge required to fill the dip. The amount can be controlled.
  • the control gate 664 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the gate insulating film 665 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the photodetector 600F can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 62A is a vertical cross-sectional view showing the structure of the photodetector 600G according to the seventh variation.
  • FIG. 62B is a plan view of the photodetector 600G according to the seventh variation as viewed from the second surface side.
  • the photodetector 600G may be further provided with an insulating layer 670 surrounding the second region 620G and the fourth region 625G in the in-plane direction of the semiconductor substrate.
  • the second region 620G and the fourth region 625G are provided in an island shape substantially in the center of the pixel region defined by the pixel separation layer 650, and cover the periphery of the second region 620G and the fourth region 625G.
  • the insulating layer 670 may be provided.
  • the insulating layer 670 surrounds the second region 620G and the fourth region 625G in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 620G in the thickness direction of the semiconductor substrate.
  • the insulating layer 670 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the size of the capacitance generated in the second region 620G can be made smaller. Further, by surrounding the insulating layer 670 around the second region 620G, the region where the capacitance is generated in the second region 620G can be limited to the semiconductor substrate on the inner side of the second region 620G. According to this, the insulating layer 670 can control the amount of electric charge required to fill the dip of the energy band structure formed on the second electrode 621 side by reducing the capacitance generated in the second region 620G. it can. Therefore, the photodetector 600G can operate with a smaller number of photoelectrons.
  • the photodetector 600G can further improve the detection characteristics of incident light.
  • FIG. 63A is a vertical cross-sectional view showing the structure of the photodetector 600H according to the eighth variation.
  • FIG. 63B is a plan view of the photodetector 600H according to the eighth variation as viewed from the first surface side.
  • the PN / i / PN diode is not in the thickness direction of the semiconductor substrate but in the plane of the semiconductor substrate with respect to the photodetector 600A according to the first variation.
  • the points formed in the direction are different.
  • the first electrode 611 and the second electrode 621 are provided on the first surface of the semiconductor substrate, respectively.
  • the first region 610H is provided in a part of the region on the first surface side of the semiconductor substrate along one side of the pixel separation layer 650 that defines the rectangular pixel region.
  • the fifth region 615H is provided in a region opposite to the pixel separation layer 650 with the first region 610H interposed therebetween so as to cover the side surface and the bottom surface of the first region 610H.
  • the second region 620H is provided in a part of the region on the first surface side of the semiconductor substrate along the other side facing one side of the pixel separation layer 650 that defines the rectangular pixel region.
  • the fourth region 625H is provided in a region opposite to the pixel separation layer 650 with the second region 620H interposed therebetween so as to cover the side surface and the bottom surface of the second region 620H.
  • the third region 630 is provided in the region between the fifth region 615H and the fourth region 625H.
  • the first electrode 611 is provided on the first region 610H exposed on the first surface of the semiconductor substrate, and the second electrode 621 is provided on the second region 620H exposed on the first surface of the semiconductor substrate. Be done.
  • the photodetector 600G can form the first electrode 611 and the second electrode 621 on the same surface of the semiconductor substrate, so that the electrodes can be formed more easily.
  • FIG. 64A is a vertical cross-sectional view showing the structure of the photodetector 600I according to the ninth variation.
  • FIG. 64B is a plan view of the photodetector 600I according to the ninth variation as viewed from the first surface side.
  • the photodetector 600I has a first region 610I, a fifth region 615I, a fourth region 625I, and a second region 620I with respect to the photodetector 600H according to the eighth variation. Is different in that is provided extending from the first surface of the semiconductor substrate to the second surface opposite to the first surface. According to this, the first region 610I and the second region 620I cover the interface between the pixel separation layer 650 and the third region 630, so that the induction of electric charge at the interface can be suppressed by the pinning effect.
  • the photodetector 600I can suppress the induction of electric charge at the interface between the semiconductor substrate and the pixel separation layer 650, so that noise can be further reduced.
  • FIG. 65 is a vertical cross-sectional view showing the structure of the photodetector 600J according to the tenth variation.
  • the first control electrode 663J-1 is further electrically connected to the fifth region 615J with respect to the photodetector 600H according to the eighth variation, and the fourth The difference is that the second control electrode 663J-2 is further electrically connected to the region 625J.
  • the fifth region 615J is provided so as to cover the side surface and the bottom surface of the first region 610J
  • the first control electrode 663J-1 is the fifth region 615J exposed on the first surface of the semiconductor substrate. It may be provided on the top.
  • the fourth region 625J is provided so as to cover the side surface and the bottom surface of the second region 620J
  • the second control electrode 663J-2 is provided on the fourth region 625J exposed on the first surface of the semiconductor substrate. May be done.
  • the first control electrode 663J-1 and the second control electrode 663J-2 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or poly. It may be provided of silicon (poly-Si) or other conductive material.
  • the first control electrode 663J-1 can control the height of the potential barrier formed on the first electrode 611 side by controlling the potential of the fifth region 615J. Further, the second control electrode 663J-2 is necessary for controlling the potential of the fourth region 625J to fill the dip depth of the energy band structure formed on the second electrode 621 side and the dip. The amount of charge can be controlled.
  • the photodetector 600J can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 66A is a vertical cross-sectional view showing the structure of the photodetector 600K according to the eleventh variation.
  • FIG. 66B is a plan view seen from the first surface side showing the structure of the photodetector 600K according to the eleventh variation.
  • the photodetector 600K is provided with a first control gate 664K-1 further on the fifth region 615K with respect to the photodetector 600H according to the eighth variation.
  • the difference is that the second control gate 664K-2 is further provided on the fourth region 625K.
  • the first control gate 664K-1 may be provided via the gate insulating film 665K-1 on the fifth region 615K provided so as to cover the side surface and the bottom surface of the first region 610K. ..
  • the second control gate 664K-2 may be provided via the gate insulating film 665K-2 on the fourth region 625K provided so as to cover the side surface and the bottom surface of the second region 620K.
  • the first control gate 664K-1 and the second control gate 664K-2 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or poly. It may be provided of silicon (poly-Si) or other conductive material.
  • the gate insulating films 665K-1 and 665K-2 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. ..
  • the first control gate 664K-1 can control the height of the potential barrier formed on the first electrode 611 side by controlling the potential of the fifth region 615K by applying a voltage. Further, the second control gate 664K-2 fills the dip depth of the energy band structure formed on the second electrode 621 side and the dip by controlling the potential of the fourth region 625K by applying a voltage. The amount of charge required for this can be controlled.
  • the photodetector 600K can control the detection characteristics of the incident light with higher accuracy.
  • FIG. 67 is a vertical cross-sectional view showing the structure of the photodetector 600L according to the twelfth variation.
  • the photodetector 600L has a first region 610L, a fifth region 615L, a third region 630L, a fourth region 625L, and a second region with respect to the photodetector 600A according to the first variation.
  • the difference is that the semiconductor substrate including the region 620L is formed of a semiconductor other than silicon.
  • the semiconductor substrate including the first region 610L, the fifth region 615L, the third region 630L, the fourth region 625L, and the second region 620L is formed of silicon germanium (SiGe), a group III-V compound semiconductor, or the like. You may.
  • the photodetector 600L can control the wavelength band of the detectable light.
  • the twelfth variation can be combined with any of the first to eleventh variations described above and the thirteenth and fourteenth variations described later.
  • FIG. 68 is a vertical cross-sectional view showing the structure of the photodetector 600M according to the thirteenth variation.
  • a metal layer 681 may be further provided inside the pixel separation layer 650. Since the metal layer 681 has a light-shielding property, it is possible to prevent light incident on the first surface of the semiconductor substrate from an oblique direction from entering adjacent pixels.
  • the metal layer 681 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
  • the photodetector 600M can prevent the intrusion of light between pixels by the metal layer 681, so that crosstalk between pixels can be further suppressed.
  • the thirteenth variation can be combined with any of the first to twelfth variations described above and the fourteenth variation described later.
  • FIG. 69 is a vertical cross-sectional view showing the structure of the photodetector 600N according to the fourteenth variation.
  • the photodetector 600N may further include a reflective layer 682 provided on the second surface side of the semiconductor substrate via an interlayer insulating film (not shown).
  • the reflective layer 682 can reflect the light incident on the second surface side of the semiconductor substrate after being incident on the first surface of the semiconductor substrate and then passing through the third region 630. According to this, since the reflective layer 682 can confine the incident light in the semiconductor substrate including the third region 630, the photoelectric conversion efficiency in the third region 630 can be improved.
  • the reflection layer 682 may be provided so as to spread over the entire surface of the pixel region defined by the pixel separation layer 650.
  • the reflective layer 682 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
  • the photodetector 600N can improve the photoelectric conversion efficiency in the third region 630, so that the detection sensitivity of the incident light can be improved.
  • the 14th variation can be combined with any of the 1st to 13th variations described above.
  • a layer containing a second conductive impurity at a low concentration (for example, P layer) at the interface between the semiconductor layer such as silicon and the insulator layer, or a negative fixed charge or chargeability is applied.
  • a layer to have is provided.
  • the layer containing the second conductive type impurity can rebond the electrons at the interface state generated at the interface between the semiconductor layer and the insulator layer with the holes in the layer, so that the layer is insulated from the semiconductor layer. It is possible to suppress the generation of false signals or dark currents due to electrons generated at the interface with the body layer. Further, since the layer having a negative fixed charge or chargeability can form a hole accumulation layer (hole accumulation layer) at the layer interface by a negative electric field, the charge at the interface between the semiconductor layer and the insulator layer The generation of (electrons) can be suppressed.
  • the charge (electrons) generated at the interface between the semiconductor layer and the insulator layer can be extinguished by the hole storage layer, so that the semiconductor layer and the insulator layer can be eliminated. It is possible to suppress the generation of false signals or dark currents due to the electrons generated at the interface with.
  • a false signal is provided by providing a layer (hereinafter, also referred to as a pinning layer) that absorbs charges generated at the interface as described above at the interface between the semiconductor layer and the insulator layer.
  • a layer hereinafter, also referred to as a pinning layer
  • the generation of dark current can be further suppressed.
  • the photodetector according to the present embodiment will be described as a first to twelfth structural example using a layer containing a second conductive impurity as a pinning layer, and a negative fixed charge or chargeability will be described.
  • a structural example using the provided layer as a pinning layer will be described as 13th to 18th structural examples.
  • FIG. 70 is a vertical cross-sectional view showing the structure of the photodetector 700A according to the first structural example.
  • 71A and 71B are top views showing an example of the planar structure of the photodetector 700A according to the first structural example.
  • the cross-sectional structure of the photodetector 700A shown in FIG. 70 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 71A and 71B.
  • the photodetector 700A includes, for example, a first region 710, a second region 720, a third region 730, a pinning layer 741, an insulating film 740, a control gate 761, and gate insulation. It includes a film 762.
  • the first region 710 is a first conductive type region (for example, N + layer) provided on a semiconductor substrate such as silicon (Si).
  • the second region 720 is a second conductive type region (for example, P + layer) provided on a semiconductor substrate such as silicon (Si).
  • the third region 730 is a third conductive type region (for example, the i-layer) provided in a region excluding the first region 710 and the second region 720 of the semiconductor substrate such as silicon (Si).
  • the control gate 761 is a gate electrode provided on the semiconductor substrate via the gate insulating film 762.
  • the control gate 761 is provided to control the potential barrier in the third region 730 by applying a voltage.
  • the control gate 761 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the gate insulating film 762 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the control gate 761 is provided, for example, around the second region 720.
  • the control gates 761 may be provided on both sides of the second region 720 in the arrangement direction of the first region 710 and the second region 720, respectively.
  • the control gate 761 may be provided so as to surround the entire circumference of the second region 720.
  • the region between the first region 710 and the control gate 761 becomes the light absorption region 731 in the photodetector 700A.
  • the photodetector 700A can detect the light incident on the light absorption region 731.
  • a first electrode (not shown) that functions as a cathode electrode is electrically connected to the first region 710.
  • a second electrode (not shown) that functions as an anode electrode is electrically connected to the second region 720.
  • the insulating film 740 is provided on the surface of a semiconductor substrate such as silicon (Si).
  • the insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the insulating film 740 may be, for example, a natural oxide film formed on the surface of the silicon substrate, or may be a protective layer separately provided on the surface of the semiconductor substrate to protect the third region 730.
  • the pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is provided at the interface between the semiconductor substrate such as silicon (Si) and the insulating film 740.
  • the distance between the pinning layer 741 and the first region 710 or the second region 720 can be set so that the maximum electric field during operation of the photodetector 700A is less than 0.5 MeV / cm.
  • the pinning layer 741 may be provided, for example, at the interface between the semiconductor substrate of the light absorption region 731 and the insulating film 740 provided between the first region 710 and the control gate 761.
  • the pinning layer 741 can recombine the electrons at the interface state generated at the interface between the semiconductor substrate and the insulating film 740 with the holes in the pinning layer 741. Therefore, the pinning layer 741 can prevent electrons generated at the interface between the semiconductor substrate and the insulating film 740 from flowing into the depletion layer of the third region 730 and forming a false signal or a dark current.
  • the photodetector 700A can suppress the generation of false signals or dark currents.
  • FIG. 72 is a vertical cross-sectional view showing the structure of the photodetector 700B according to the second structural example.
  • 73A and 73B are top views showing an example of the planar structure of the photodetector 700B according to the second structural example.
  • the cross-sectional structure of the photodetector 700B shown in FIG. 72 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 73A and 73B.
  • the pinning layer 741 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate with respect to the photodetector 700A according to the first structural example. The difference is that it is spread out in. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 761 are provided.
  • the photodetector 700B can further suppress the generation of false signals or dark currents due to the electrons generated at the interface between the semiconductor substrate and the insulating film 740.
  • FIG. 74 is a vertical cross-sectional view showing the structure of the photodetector 700C according to the third structural example.
  • 75A, 75B, 77A, and 77B are plan views showing an example of a region in which the pinning layer 741 is formed on the surface side of the semiconductor layer including the third region 730.
  • 76A, 76B, 78A, and 78B are plan views showing an example of a region in which the pinning layer 741 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782.
  • the cross-sectional structure of the photodetector 700C shown in FIG. 74 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 75A to 78B.
  • the photodetector 700C includes, for example, a first region 710, a second region 720, a third region 730, a pinning layer 741, an insulating film 740, a control gate 763, and gate insulation.
  • a film 764, an embedded insulating film 782, and a support substrate 781 are provided.
  • the support substrate 781 is, for example, a semiconductor substrate such as a silicon (Si) substrate.
  • the embedded insulating film 782 is formed of, for example, silicon oxide (SiO x ) and is provided on the support substrate 781. Further, a semiconductor layer made of silicon (Si) or the like is provided on the embedded insulating film 782.
  • the semiconductor substrate on which the photodetector 700C is formed is a so-called SOI (Silicon On Insulator) substrate.
  • the support substrate 781 corresponds to the support substrate of the SOI substrate
  • the embedded insulating film 782 corresponds to the BOX (Buried OXide) layer of the SOI substrate
  • the semiconductor layer on the embedded insulating film 782 corresponds to the active layer of the SOI substrate.
  • the first region 710 is a first conductive type region (for example, N + layer) provided in the semiconductor layer on the embedded insulating film 782.
  • the second region 720 is a second conductive type region (for example, P + layer) provided in the semiconductor layer on the embedded insulating film 782.
  • the third region 730 is a third conductive type region (for example, the i-layer) provided in the semiconductor layer between the first region 710 and the second region 720.
  • the first region 710 and the second region 720 may extend in the thickness direction of the semiconductor layer and may be provided from the surface of the semiconductor layer until the embedded insulating film 782 is reached.
  • a first electrode (not shown) that functions as a cathode electrode is electrically connected to the first region 710.
  • a second electrode (not shown) that functions as an anode electrode is electrically connected to the second region 720.
  • the control gate 763 is provided so as to be embedded in the gate insulating film 764 formed on the semiconductor layer.
  • the control gate 763 may be provided, for example, in a region adjacent to the first region 710 or the second region 720.
  • the control gate 763 can control the potential barrier in the third region 730 by applying a voltage.
  • the control gate 763 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
  • the gate insulating film 764 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the first region 710 and the second region 720 may be provided extending in one direction in the in-plane direction of the semiconductor layer, respectively.
  • a plurality of control gates 763 may be provided in a region between the first region 710 and the second region 720 adjacent to each of the first region 710 and the second region 720.
  • the region between the plurality of control gates 763 provided in the arrangement direction of the first region 710 and the second region 720 is the light absorption region 731 in the photodetector 700C.
  • the first region 710 and the second region 720 may be provided extending in one direction in the in-plane direction of the semiconductor layer, respectively.
  • the control gate 763 may be provided in the region between the first region 710 and the second region 720 in an annular rectangular shape. Specifically, the control gate 763 may be provided in an annular rectangular shape composed of two sides adjacent to each of the first region 710 and the second region 720 and two sides connecting the two sides to each other. Good.
  • the region inside the annular rectangular control gate 763 is the light absorption region 731 in the photodetector 700C.
  • the insulating film 740 is provided on the surface of the semiconductor layer including the third region 730.
  • the insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the insulating film 740 may be, for example, a natural oxide film formed on the surface of the semiconductor layer, or may be a protective layer separately provided on the surface of the semiconductor layer in order to protect the third region 730.
  • the pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is an interface between the semiconductor layer including the third region 730 and the insulating film 740, or a third region. It is provided at one or both of the interfaces between the semiconductor layer including 730 and the embedded insulating film 782.
  • the pinning layer 741 can recombine the electrons at the interface state generated at the interface between the semiconductor layer including the third region 730 and the insulating film 740 or the embedded insulating film 782 with the holes in the pinning layer 741. Therefore, the pinning layer 741 suppresses that electrons generated at the interface between the semiconductor layer and the insulating film 740 or the embedded insulating film 782 flow into the depletion layer of the third region 730 and become a false signal or a dark current. Can be done.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the insulating film 740 is formed in the light absorption region 731 between or inside the control gate 763. It may be provided in.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the insulating film 740 is provided not only on the light absorption region 731 but also on the entire surface of the semiconductor substrate. It may be spread out.
  • the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 763 are provided.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is located between the first region 710 and the second region 720. It may be provided in the area.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate. It may be spread over and provided.
  • the pinning layer 741 may be provided so as to further surround the region in which the first region 710 and the second region 720 are provided. That is, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 may extend to the bottom of the control gate 763.
  • the photodetector 700C can suppress the generation of false signals or dark currents even if the formed substrate is an SOI substrate.
  • FIG. 79 is a vertical cross-sectional view showing the structure of the photodetector 700D according to the fourth structural example.
  • 80A, 80B, 82A, and 82B are plan views showing an example of a region where the pinning layer 741 is formed on the surface side of the charge generation layer 783.
  • 81A, 81B, 83A, and 83B are plan views showing an example of a region in which the pinning layer 741 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782.
  • the cross-sectional structure of the photodetector 700D shown in FIG. 79 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 80A to 83B.
  • the charge generation layer 783 is provided on the semiconductor layer including the third region 730 with respect to the photodetector 700C according to the third structural example, and the charge generation layer 783 is provided.
  • the difference is that the pinning layer 741 is formed on the surface of 783.
  • the charge generation layer 783 is formed of a semiconductor material and is provided in the region between or inside the control gates 763 on the semiconductor layer.
  • the charge generation layer 783 can generate an electric charge by photoelectrically converting the incident light.
  • the charge generation layer 783 may be formed of one of germanium (Ge), gallium arsenide (GaAs), or silicon germanium (SiGe) or a mixture thereof, and is a low-concentration or high-concentration conductive type. It may be formed of silicon doped with impurities.
  • the charge generation layer 783 can, for example, photoelectrically convert light in a wavelength band that is not photoelectrically converted in the third region 730. Further, the charge generation layer 783 can improve the quantum efficiency of the photodetector 700D by photoelectrically converting the incident light in the same manner as in the third region 730, for example.
  • the control gate 763 is provided in the region between the first region 710 and the second region 720 extending in the same direction in each of the first region 710 and the second region 720. A plurality of them may be provided adjacent to each other.
  • the region between each of the control gates 763 in the arrangement direction of the first region 710 and the second region 720 is the light absorption region 731 in the photodetector 700D.
  • the control gate 763 may be provided in an annular rectangular shape in a region between the first region 710 and the second region 720 extending in the same direction. .. Specifically, the control gate 763 may be provided in an annular rectangular shape composed of two sides adjacent to each of the first region 710 and the second region 720 and two sides connecting the two sides to each other. Good.
  • the region inside the annular rectangular control gate 763 is the light absorption region 731 in the photodetector 700D.
  • the insulating film 740 is provided on the surface of the charge generation layer 783.
  • the insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the insulating film 740 may be, for example, a natural oxide film formed on the surface of the charge generation layer 783, or may be a protective layer separately provided to protect the charge generation layer 783.
  • the pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is a semiconductor including the interface between the charge generation layer 783 and the insulating film 740 or the third region 730. It is provided on one or both of the interfaces between the layer and the embedded insulating film 782.
  • the electric charge generated at the interface between the charge generation layer 783 and the insulating film 740 or the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 flows into the depletion layer of the third region 730. It is possible to suppress a false signal or a dark current.
  • the pinning layer 741 provided at the interface between the charge generation layer 783 and the insulating film 740 is provided in the light absorption region 731 between the control gates 763 or inside. May be good.
  • the pinning layer 741 provided at the interface between the charge generation layer 783 and the insulating film 740 is provided not only in the light absorption region 731 but also over the entire surface of the semiconductor substrate. You may.
  • the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 763 are provided.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is located between the first region 710 and the second region 720. It may be provided in a plane region.
  • the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate. It may be spread over and provided. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710 and the second region 720 are provided. That is, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 may extend to the bottom of the control gate 763.
  • the photodetector 700D can improve the photoelectric conversion characteristic with respect to the incident light.
  • FIG. 84 is a vertical cross-sectional view showing the structure of the photodetector 700E according to the fifth structural example.
  • the substrate on which the photodetector 700E is formed is not an SOI substrate but a semiconductor substrate such as a silicon substrate with respect to the photodetector 700C according to the third structural example.
  • the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and the insulating film 740.
  • the photodetector 700E can reduce the manufacturing cost by using a cheaper substrate.
  • FIG. 85 is a vertical cross-sectional view showing the structure of the photodetector 700F according to the sixth structural example.
  • the monolithic structure 784 is provided on the semiconductor layer including the third region 730 with respect to the photodetector 700C according to the third structural example, and the monolithic structure 784 is provided.
  • the difference is that the pinning layer 741 is formed on the side surface.
  • the monolithic structure 784 is a structure formed by processing one semiconductor substrate, and is provided between or in the inner region of the control gate 763 on the semiconductor layer.
  • the monolithic structure 784 is a light absorption layer that photoelectrically converts incident light, and may contain, for example, silicon (Si), germanium (Ge), silicon carbide (SiC), or the like. According to this, the photodetector 700F can improve the photoelectric conversion characteristic with respect to the incident light.
  • the contact layer 785 may be provided on the surface of the monolithic structure 784 opposite to the laminated surface with the third region 730.
  • the contact layer 785 is, for example, a second conductive type region (for example, a P + layer).
  • the photodetector 700F can control the potential of the monolithic structure 784 by applying a voltage to the monolithic structure 784 via the contact layer 785.
  • An insulating film 740 is provided on the side surface of the monolithic structure 784.
  • the insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
  • the insulating film 740 may be, for example, a natural oxide film formed on the side surface of the monolithic structure 784, or may be a protective layer separately provided to protect the monolithic structure 784.
  • the pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720.
  • the pinning layer 741 is provided at least one of the interface between the side surface of the monolithic structure 784 and the insulating film 740 and the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782.
  • the electric charge generated at the interface between the side surface of the monolithic structure 784 and the insulating film 740 or the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 flows into the depletion layer of the third region 730. , False signal or dark current can be suppressed.
  • the photodetector 700F can suppress the generation of a false signal or a dark current even when the monolithic structure 784 is provided.
  • FIG. 86 is a vertical cross-sectional view showing the structure of the photodetector 700G according to the seventh structural example.
  • the photodetector 700G is different from the photodetector 700D according to the fourth structural example in that the substrate on which the photodetector 700G is formed is a semiconductor substrate such as a silicon substrate.
  • the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and the insulating film 740.
  • the photodetector 700G can reduce the manufacturing cost by using a cheaper substrate.
  • FIG. 87 is a vertical cross-sectional view showing the structure of the photodetector 700H according to the eighth structural example.
  • the photodetector 700H is an SOI substrate on which the photodetector 700H is formed does not have a support substrate 781, as opposed to the photodetector 700F according to the sixth structural example. different.
  • the pinning layer 741 may be provided on at least one of the interface between the side surface of the monolithic structure 784 and the insulating film 740, and the semiconductor layer including the third region 730 and the monolithic structure 784.
  • the photodetector 700H can make the chip smaller by lowering the overall configuration.
  • FIG. 88 is a vertical cross-sectional view showing the structure of the photodetector 700I according to the ninth structural example.
  • the first region 710 is the surface opposite to the surface on which the second region 720 of the semiconductor substrate is provided.
  • the difference is that it is provided in. That is, in the photodetector 700I, the first region 710, the third region 730, and the second region 720 are arranged in the thickness direction of the semiconductor substrate with respect to the photodetector 700B according to the second structural example. Is different.
  • the second region 720 is provided on the second surface side of the semiconductor substrate.
  • the first region 710 is provided on the first surface side opposite to the second surface on which the second region 720 of the semiconductor substrate is provided.
  • the third region 730 is a third conductive type region (for example, layer i), and is provided between the first region 710 and the second region 720 of the semiconductor substrate.
  • the insulating film 740 is provided on the second surface of the semiconductor substrate on which the second region 720 is provided. Therefore, the pinning layer 741 may be provided at the interface between the second surface provided with the second region 720 of the semiconductor substrate and the insulating film 740.
  • the photodetector 700I can arrange the first region 710, the third region 730, and the second region 720 in the thickness direction of the semiconductor substrate, so that the chip area is made smaller. It is possible.
  • FIG. 89 is a vertical cross-sectional view showing the structure of the photodetector 700J according to the tenth structural example.
  • the photodetector 700J is different from the photodetector 700I according to the ninth structural example in that a plurality of second regions 720 are provided.
  • a plurality of second regions 720 are provided on the second surface side of the semiconductor substrate so as to be separated from each other. Further, a control gate 761 is provided on the semiconductor substrate around each of the second regions 720 via a gate insulating film 762. The control gates 716 may be provided on both sides of the second region 720, or may be provided so as to surround the entire circumference of the second region 720.
  • the region between each of the plurality of second regions 720 and the control gate 761 is the light absorption region 731, and the insulating film 740 is provided on the semiconductor substrate of the light absorption region 731. Therefore, the pinning layer 741 may be provided at the interface between the second surface provided with the light absorption region 731 of the semiconductor substrate and the insulating film 740.
  • the photodetector 700J can more efficiently extract the current from the third region 730.
  • FIG. 90 is a vertical cross-sectional view showing the structure of the photodetector 700K according to the eleventh structural example.
  • the photodetector 700K includes a first region 710, a first electrode 711, a second region 720, a second electrode 721, a third region 730, a reset region 791, and a reset electrode. It includes a 766, a gate insulating film 767, a ground region 792, a ground electrode 765, an in-plane separation layer 753, and a pinning layer 741.
  • the first region 710, the first electrode 711, the second region 720, the second electrode 721, and the third region 730 are as described in the photodetector 700A and the like according to the first structural example. The explanation in is omitted.
  • the first region 710, the first electrode 711, the second region 720, and the second electrode 721 are provided on the same surface side of the semiconductor substrate.
  • the reset region 791 is a first conductive type region (for example, N + layer).
  • a reset electrode 766 is provided on the reset region 791 via a gate insulating film 767. By applying a voltage from the reset electrode 766, the reset region 791 can discharge the electric charge remaining inside the third region 730 to the outside of the third region 730.
  • the reset area 791 may be provided on both sides of the second area 720, or may be provided so as to surround the circumference of the second area 720.
  • the ground region 792 is a second conductive type region (for example, P + layer).
  • the ground region 792 is electrically connected to the ground electrode 765 to supply the ground potential to the third region 730.
  • the ground region 792 may be provided so as to be separated from the first region 710 and the second region 720.
  • the in-plane separation layer 753 is provided between each of the first region 710, the second region 720, the reset region 791, and the ground region 792 provided on the same side of the semiconductor substrate including the third region 730.
  • the in-plane separation layer 753 is formed of an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material, and has a first region 710 and a second region.
  • Each of the 720, the reset region 791, and the ground region 792 is electrically separated from each other.
  • the in-plane separation layer 753 may be provided extending to a region deeper than the formation depth of each of the first region 710, the second region 720, the reset region 791, and the ground region 792.
  • the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and each of the in-plane separation layers 753 which are insulators. Specifically, the pinning layer 741 may be provided so as to cover the side surface and the bottom surface of the in-plane separation layer 753 embedded in the semiconductor substrate.
  • the photodetector 700K can suppress the generation of false signals or dark currents and improve the electrical separability between the electrodes.
  • FIG. 91 is a vertical cross-sectional view showing the structure of the photodetector 700L according to the twelfth structural example.
  • the photodetector 700L includes, for example, a first region 710, a second region 720, a third region 730, a first electrode 711, a via 712, and a first surface insulating layer 751.
  • a pixel separation layer 750, a second electrode 721, a control gate 761, and a gate insulating film 762 are provided.
  • the first region 710 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 720 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the third region 730 is a third conductive type region (for example, layer i) provided between the first region 710 and the second region 720 of a semiconductor substrate such as silicon (Si).
  • the first electrode 711 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 751, and is electrically connected to the first region 710 via a via 712 or the like penetrating the first surface insulating layer 751. Connecting.
  • the first electrode 711 functions as, for example, a cathode electrode.
  • the first electrode 711 is provided, for example, so as to straddle the pixel separation layer 750 along the boundary between pixels, and is electrically connected to the first region 710 of each pixel by a via 712 provided for each pixel. ..
  • the pixel separation layer 750 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other.
  • the pixel separation layer 750 may be provided in a grid pattern, for example, along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
  • the second electrode 721 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 720.
  • the second electrode 721 functions as, for example, an anode electrode.
  • the control gate 761 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 762.
  • the control gate 761 can control the potential barrier in the third region 730 by applying a voltage.
  • the first electrode 711, via 712, second electrode 721, and control gate 761 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta). It may be provided by polysilicon (poly-Si) or other conductive material.
  • the first surface insulating layer 751, the pixel separation layer 750, and the gate insulating film 762 are made of an insulator such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), or a so-called low-k material. It may be provided.
  • the pinning layer 741 may be provided at the interface between the pixel separation layer 750 and the third region 730. Specifically, the pinning layer 741 may be provided so as to cover the side surface of the pixel separation layer 750.
  • the photodetector 700L can suppress the generation of false signals or dark currents even when it is provided as a back-illuminated pixel array structure.
  • FIG. 92 is a vertical cross-sectional view showing the structure of the photodetector 700M according to the thirteenth structural example.
  • 93A and 93B are top views showing an example of the planar structure of the photodetector 700M according to the thirteenth structural example.
  • the cross-sectional structure of the photodetector 700M shown in FIG. 92 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 93A and 93B.
  • the thirteenth structural example replaces the second conductive type pinning layer 741 in the first structural example with a pinning layer 742 having a negative fixed charge or chargeability.
  • a pinning layer 742 having a negative fixed charge or chargeability.
  • the pinning layer 742 may be laminated on the semiconductor substrate as shown in FIG. 92, or may be embedded inside the semiconductor substrate as shown in FIG. 96 described later.
  • the pinning layer 742 is a layer having a negative fixed charge or a layer having a negative charge.
  • a pinning layer 742 includes, for example, silicon oxide (SiO 2 ), silicon nitride (SiN), silicon oxynitride (SiON), hafnium oxide (HfO 2 ), aluminum oxide (Al 2 O 3 ), zirconium oxide (ZrO).
  • the pinning layer 742 may be formed as a multilayer film in which a plurality of the above materials are combined and laminated.
  • the pinning layer 742 may be formed of any other material as long as it is an insulating material having a negative fixed charge or a negative charge.
  • the photodetector 700M can suppress the generation of false signals or dark currents.
  • FIG. 94 is a vertical cross-sectional view showing the structure of the photodetector 700N according to the 14th structural example.
  • 95A and 95B are top views showing an example of the planar structure of the photodetector 700N according to the 14th structural example.
  • the cross-sectional structure of the photodetector 700N shown in FIG. 94 corresponds to the cross-sectional structure at the AA cut surface of FIGS. 95A and 95B.
  • the second conductive type pinning layer 741 in the second structural example has a negative fixed charge or chargeability described in the thirteenth structural example.
  • the pinning layer 742 may be laminated on the semiconductor substrate as shown in FIG. 94, or may be embedded inside the semiconductor substrate as shown in FIG. 96 described later.
  • the photodetector 700N can further suppress the generation of false signals or dark currents due to the electrons generated at the interface between the semiconductor substrate and the insulating film 740.
  • FIG. 96 is a vertical cross-sectional view showing the structure of the photodetector 700O according to the fifteenth structural example.
  • 97A, 97B, 99A, and 99B are plan views showing an example of a region in which the pinning layer 742 is formed on the surface side of the semiconductor layer including the third region 730.
  • 98A, 98B, 100A, and 100B are plan views showing an example of a region in which the pinning layer 742 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782.
  • the cross-sectional structure of the photodetector 700O shown in FIG. 96 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 97A to 100B.
  • the second conductive type pinning layer 741 in the third structural example has a negative fixed charge or chargeability described in the thirteenth structural example.
  • the pinning layer 742 may be embedded inside the semiconductor substrate as shown in FIG. 96, or may be laminated on the semiconductor substrate as shown in FIGS. 92 and 94 described above.
  • the photodetector 700O can suppress the generation of false signals or dark currents even if the formed substrate is an SOI substrate.
  • FIG. 101 is a vertical cross-sectional view showing the structure of the photodetector 700P according to the sixteenth structural example.
  • 102A, 102B, 104A, and 104B are plan views showing an example of a region where the pinning layer 742 is formed on the surface side of the charge generation layer 783.
  • 103A, 103B, 105A, and 105B are plan views showing an example of a region in which the pinning layer 742 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782.
  • the cross-sectional structure of the photodetector 700P shown in FIG. 101 corresponds to the cross-sectional structure of the AA cut surface in FIGS. 102A to 105B.
  • the second conductive type pinning layer 741 in the fourth structural example has a negative fixed charge or chargeability described in the thirteenth structural example.
  • the pinning layer 742 may be embedded inside the charge generation layer 783 as shown in FIG. 101, or may be laminated on the charge generation layer 783 as shown in FIGS. 92 and 94 described above. Good.
  • the photodetector 700P can improve the photoelectric conversion characteristic with respect to the incident light.
  • FIG. 106 is a vertical cross-sectional view showing the structure of the photodetector 700Q according to the 17th structural example.
  • the second conductive type pinning layer 741 in the 11th structural example is the pinning layer having a negative fixed charge or chargeability described in the 13th structural example. Corresponds to the structure replaced by 742. Therefore, detailed description of each configuration here will be omitted.
  • the photodetector 700Q can suppress the generation of false signals or dark currents and improve the electrical separability between the electrodes.
  • FIG. 107 is a vertical cross-sectional view showing the structure of the photodetector 700R according to the eighteenth structural example.
  • the second conductive type pinning layer 741 in the twelfth structural example is the pinning layer having a negative fixed charge or chargeability described in the thirteenth structural example. Corresponds to the structure replaced by 742. Therefore, detailed description of each configuration here will be omitted.
  • the photodetector 700R can suppress the generation of false signals or dark currents even when it is provided as a back-illuminated pixel array structure.
  • FIG. 108A is a plan view of the photodetector 800 according to the present embodiment as viewed from the second surface side.
  • FIG. 108B is a vertical cross-sectional view showing the structure of the photodetector 800 on the AA cut surface of FIG. 108A.
  • FIG. 108C is a vertical cross-sectional view showing the structure of the photodetector 800 on the B-BB cut surface of FIG. 108A.
  • FIG. 108A is a plan view of the photodetector 800 according to the present embodiment as viewed from the second surface side.
  • FIG. 108B is a vertical cross-sectional view showing the structure of the photodetector 800 on the AA cut surface of FIG. 108A.
  • FIG. 108C is a vertical cross-sectional view showing the structure of the photodetector 800 on the B-BB cut surface of FIG. 108A.
  • FIG. 109 is a plan view showing an example of arrangement of pixel transistors included in the pixel circuit included in the photodetector 800.
  • FIG. 110 is a circuit diagram showing an example of an equivalent circuit of a pixel circuit included in the DPD sensor and the photodetector 800 that functions as a PD.
  • the photodetector 800 includes, for example, a first region 810, a second region 820, a third region 830, a first electrode 811 and a second electrode 821, and a control gate. It includes a CG, a first conductive region 891, a transfer gate TRG, a floating diffusion FD, and an extraction electrode 893.
  • the first region 810 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 820 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the second region 820 may be provided, for example, in an island shape substantially in the center of the rectangular pixel region.
  • the third region 830 is provided between the first region 810 and the second region 820 of the semiconductor substrate such as silicon (Si), and is a first conductive type region having a lower concentration of conductive impurities than the first region 810. (For example, N-layer).
  • the first electrode 811 is provided on the first surface of the semiconductor substrate and is electrically connected to the first region 810.
  • the first electrode 811 functions as, for example, a cathode electrode.
  • the second electrode 821 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 820.
  • the second electrode 821 functions as, for example, an anode electrode.
  • the control gate CG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown).
  • the control gate CG can control the potential barrier in the third region 830 by applying a voltage.
  • the control gate CG may be provided on both sides of the second region 820 in the first direction in the plane of the semiconductor substrate (that is, the extending direction of the AA cut surface of FIG. 108A).
  • the first conductive type region 891 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate.
  • the first conductive region 891 is provided, for example, so that the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830.
  • the first conductive type region 891 extends from the second region 820 in the second direction orthogonal to the first direction in the plane of the semiconductor substrate (that is, the extending direction of the B-BB cut surface of FIG. 108A). Be done.
  • the floating diffusion FD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate.
  • the floating diffusion FD may be provided on the end side of the first conductive type region 891 extending in the second direction from the second region 820.
  • the transfer gate TRG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown).
  • the transfer gate TRG is provided between the second region 820 and the floating diffusion FD, and transfers the electric charge from the second region 820 to the floating diffusion FD by applying a voltage.
  • the first conductive type region 891 may be provided in a region below the transfer gate TRG and a region surrounding a region in which the floating diffusion FD is provided. According to this, the first conductive type region 891 can function as a channel for transferring charges from the second region 820 to the floating diffusion FD. Further, the first conductive type region 891 can prevent the charge photoelectrically converted in the third region 830 from directly entering the floating diffusion FD.
  • the take-out electrode 893 is provided on the first surface of the semiconductor substrate and is electrically connected to the floating diffusion FD.
  • the take-out electrode 893 can output the electric charge accumulated in the floating diffusion FD to a pixel circuit or the like.
  • the first electrode 811, the second electrode 821, the control gate CG, the transfer gate TRG, and the take-out electrode 893 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta). ), Polysilicon (poly-Si), or other conductive material.
  • the photodetector 800 includes a first region 810, a second region 820, a third region 830, a first electrode 811, a second electrode 821, and a control gate CG.
  • the photodetector 800 can function as a DPD (Dynamic Photodiode) sensor.
  • DPD Dynamic Photodiode
  • the photodetector 800 includes a first region 810, a second region 820, a third region 830, a first electrode 811, a first conductive region 891, a transfer gate TRG, and a floating region. It includes a diffusion FD and an extraction electrode 893. As a result, the photodetector 800 can function as a normal PD (Photodiode).
  • PD Photodiode
  • the electric charge taken out from the floating diffusion FD when the photodetector 800 functions as a normal PD is converted into a pixel signal by signal processing in the pixel circuit.
  • FIG. 110 shows an equivalent circuit diagram of a pixel circuit included in the photodetector 800.
  • the DPD / PD in FIG. 110 indicates a photoelectric conversion unit having a PIN diode structure with a first region 810, a third region 830, and a second region 820.
  • the pixel circuit of the DPD sensor includes a photoelectric conversion unit DPD and a switch transistor SW.
  • the photoelectric conversion unit DPD is electrically connected to the power supply Va via the switch transistor SW.
  • the pixel circuit of PD includes a photoelectric conversion unit PD, a transfer transistor TRG, a floating diffusion FD, a reset transistor RST, an amplifier transistor AMP, and a selection transistor SEL.
  • the photoelectric conversion unit PD is electrically connected to the floating diffusion FD via the transfer transistor TRG.
  • the power supply Vd is further connected to the floating diffusion FD via the reset transistor RST, and the gate of the amplifier transistor AMP is also connected.
  • the drain of the amplifier transistor AMP is connected to the power supply Vd, and the source of the amplifier transistor AMP is connected to the external output Output via the selection transistor SEL.
  • the power supply Va on the DPD sensor side and the power supply Vd on the PD side may be different power supplies or the same power supply.
  • the photodetector 800 can function as both a DPD sensor and a PD.
  • At least one or more of the pixel transistors included in the pixel circuit described above may be formed in the pixel transistor region Tr of the photodetector 800.
  • the reset transistor RST, the amplifier transistor AMP, the selection transistor SEL, or the switch transistor SW are provided at both ends of the pixel region in the first direction (that is, the extending direction of the AA cut surface of FIG. 108A). It may be formed in the pixel transistor region Tr.
  • a reset transistor RST and an amplifier transistor AMP may be formed in the pixel transistor region Tr on one side of the transfer gate TRG.
  • the selection transistor SEL and the switch transistor SW may be formed in the pixel transistor region Tr on the other side of the transfer gate TRG.
  • FIG. 111 is a timing chart showing an example of the ToF sensor operation of the photodetector 800 according to the present embodiment.
  • FIG. 112 is an explanatory diagram illustrating a light source used in the ToF sensor.
  • FIG. 113A is a vertical sectional view illustrating the state of the photodetector 800 at the timing of FIG. 111 (1), and FIG. 113B describes the state of the photodetector 800 at the timing of FIG. 111 (2).
  • FIG. 113C is a vertical cross-sectional view for explaining the state of the photodetector 800 at the timing of FIG. 111 (3).
  • a positive voltage is applied to the voltage V SW applied to the gate of the switch transistor SW to turn on the switch transistor SW.
  • the voltage Va applied to the second electrode 821 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800.
  • the voltage V con applied to the control gate CG is set to a negative voltage (for example, -1V).
  • a pulsed negative voltage V light is applied to the light source LD such as a laser diode or an LED (Light Emitting Diode) at the timing of (2) in FIG. 111.
  • the object is irradiated with pulsed light.
  • the voltage Va applied to the second electrode 821 to a positive voltage (for example, + 1V)
  • a forward bias is applied between the first region 810 and the second region 820 of the photodetector 800.
  • the voltage V con applied to the control gate CG is set to a positive voltage (for example, + 1V).
  • the photodetector 800 can calculate the distance to the object by calculating the difference between the light emission timing t2 of the light source LD and the light detection delay time t1.
  • the voltage Va applied to the second electrode 821 at the timing of (3) in FIG. 111 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800, so that the state of the photodetector 800 is reset.
  • the voltage V con applied to the control gate CG may also be set to a negative voltage (for example, -1V).
  • the photodetector 800 can detect the distance to the object for each frame.
  • the voltage V TRG applied to the gate of the transfer gate TRG, which is the pixel circuit on the PD side, and the voltage V RST applied to the gate of the reset transistor RST are 0 V throughout one frame. Also, the voltage of the take-out electrode 893 electrically connected to the floating diffusion FD does not change throughout the entire frame.
  • FIG. 114 is a timing chart showing an example of PD operation of the photodetector 800 according to the present embodiment.
  • FIG. 115A is a vertical sectional view illustrating the state of the photodetector 800 at the timing of FIG. 114 (1)
  • FIG. 115B describes the state of the photodetector 800 at the timing of FIG. 114 (2). It is a vertical sectional view.
  • FIG. 115C is a vertical cross-sectional view illustrating the state of the photodetector 800 at the timing of FIG. 114 (3)
  • FIG. 115D describes the state of the photodetector 800 at the timing of FIG. 114 (4). It is a vertical sectional view.
  • FIG. 115E is a vertical cross-sectional view illustrating a state of the photodetector 800 at the timing of FIG. 114 (5).
  • the voltage V SW applied to the gate of the switch transistor SW is set to 0 V, so that the switch transistor SW is turned off.
  • the voltage Va applied to the two electrodes 821 is 0V.
  • a pulsed voltage VRST for example, + 1V
  • the electric charge accumulated in the floating diffusion FD is discharged to the power supply Vd, and the state of the floating diffusion FD is reset.
  • the photodetector 800 photoelectrically converts the light incident on the third region 830 and stores the photoelectrically converted charge in the second region 820.
  • a pulsed voltage VRST For example, by applying + 1V
  • the electric charge accumulated in the floating diffusion FD is discharged to the power supply Vd, and the state of the floating diffusion FD is reset.
  • the charge accumulated in the second region 820 is then transferred to the floating diffusion FD by applying a pulsed voltage V TRG (for example, -3V) to the gate of the transfer transistor TRG.
  • V TRG for example, -3V
  • the signal charge is read out from the take-out electrode 893.
  • the photodetector 800 is in the same state as the timing of FIG. 114 (2) at the timing of FIG. 114 (5), so that it is possible to start receiving the incident light again.
  • the photodetector 800 converts the electric charge according to the amount of received light into an electric signal for each frame and outputs it as an image signal. be able to.
  • FIG. 116 is a block diagram showing a functional configuration when the photodetector 800 according to the present embodiment is a pixel array.
  • a DPD control circuit 801 and a DPD signal detection circuit 803, a PD control circuit 802, and a PD signal detection circuit 804 are connected to the photoelectric conversion unit DPD / PD of each pixel.
  • the DPD control circuit 801 and the DPD signal detection circuit 803 of each pixel are connected to the DPD horizontal control unit 8210, the DPD signal processing unit 8220, and the vertical control unit 8300. Further, the PD control circuit 802 and the PD signal detection circuit 804 of each pixel are connected to the PD horizontal control unit 8110, the PD signal processing unit 8120, and the vertical control unit 8300. Further, each pixel is connected to the DPD / PD switching control unit 8400 that switches the DPD operation or the PD operation of the photoelectric conversion unit DPD / PD.
  • the DPD / PD switching control unit 8400 is connected to the DPD horizontal control unit 8210, the PD horizontal control unit 8110, and each pixel.
  • the DPD / PD switching control unit 8400 switches the DPD / PD operation of each pixel by outputting the DPD / PD switching signal.
  • the DPD / PD operation switching may be performed for all pixels at once or for each predetermined pixel of the pixel array, depending on the application such as imaging or distance measurement. Further, the switching of the DPD / PD operation may be performed by dividing the time, or may be performed for each frame.
  • the vertical control unit 8300 is connected to the DPD horizontal control unit 8210 and the PD horizontal control unit 8110, and when the DPD operation and the PD operation are performed by the photoelectric conversion unit DPD / PD, the DPD horizontal control unit 8210 and the PD horizontal control unit 8300 are controlled.
  • a read signal is output to unit 8110 line by line.
  • the DPD horizontal control unit 8210 reads the DPD signal of each pixel for each column and outputs the read DPD signal to the DPD signal processing unit 8220.
  • the DPD signal processing unit 8220 processes the input DPD signal and then outputs the processed DPD signal as ToF data.
  • the PD horizontal control unit 8110 reads the PD signal of each pixel for each column and outputs the read PD signal to the PD signal processing unit 8120.
  • the PD signal processing unit 8120 processes the input PD signal and then outputs the processed PD signal as image data.
  • the ToF light source control unit 8500 is connected to the vertical control unit 8300 and the DPD signal processing unit 8220, and controls the light emission timing of the light source LD that emits light during the ToF operation.
  • the ToF light source control unit 8500 may control the signal processing of the DPD signal or the reading of the DPD signal by outputting the light emission timing signal of the light source LD to the vertical control unit 8300 and the DPD signal processing unit 8220.
  • FIG. 117A is a plan view of the photodetector 800A according to the first variation as viewed from the second surface side.
  • FIG. 117B is a vertical cross-sectional view showing the structure of the photodetector 800A on the AA cut surface of FIG. 117A.
  • FIG. 117C is a vertical cross-sectional view showing the structure of the photodetector 800A on the B-BB cut surface of FIG. 117A.
  • the photodetector 800A has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and discharge with respect to the photodetector 800 described with reference to FIGS. 108A to 108C.
  • the difference is that the electrode 897 is further provided.
  • the first conductive type region 895 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate.
  • the first conductive region 895 is provided so that, for example, the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830.
  • the first conductive type region 895 may be provided extending from the second region 820 in a direction opposite to the extending direction of the first conductive type region 891.
  • the overflow drain OFD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate.
  • the overflow drain OFD may be provided on the end side of the first conductive type region 895 extending from the second region 820.
  • the overflow gate OFG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown).
  • the overflow gate OFG is provided between the second region 820 and the overflow drain OFD, and controls the discharge of electric charge from the second region 820 to the overflow drain OFD.
  • the first conductive type region 895 may be provided in a region below the overflow gate OFG and a region surrounding the region in which the overflow drain OFD is provided. According to this, the first conductive type region 895 can function as a channel for discharging the electric charge from the second region 820 to the overflow gate OFG. Further, the first conductive type region 895 can prevent the charge photoelectrically converted in the third region 830 from directly entering the overflow drain OFD.
  • the discharge electrode 897 is provided on the first surface of the semiconductor substrate and is electrically connected to the overflow drain OFD.
  • the discharge electrode 897 is electrically connected to the power supply, and the electric charge discharged to the overflow drain OFD can be further discharged to the power supply.
  • the photodetector 800A can discharge the electric charge generated in excess of the saturated charge amount during the PD operation from the second region 820 to the overflow drain OFD.
  • the electric charge discharged to the overflow drain OFD is further discharged to the power supply via the discharge electrode 897. Therefore, the photodetector 800A can suppress the occurrence of blooming during PD operation.
  • the photodetector 800A can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 118A is a plan view of the photodetector 800B according to the second variation as viewed from the second surface side.
  • FIG. 118B is a vertical cross-sectional view showing the structure of the photodetector 800B on the AA cut surface of FIG. 118A.
  • FIG. 118C is a vertical cross-sectional view showing the structure of the photodetector 800B on the B-BB cut surface of FIG. 118A.
  • the photodetector 800B is different from the photodetector 800 described with reference to FIGS. 108A to 108C in that it further includes a pixel separation layer 850 that defines a pixel region.
  • the pixel separation layer 850 is provided so as to surround the outer periphery of the rectangular pixel region so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and electrically separate adjacent pixels from each other.
  • the formation depth of the pixel separation layer 850 may be deeper than, for example, the formation depth of the second region 820, the first conductive type region 891, and the pixel transistor region Tr.
  • the pixel separation layer 850 may be provided with an insulator such as silicon oxide (SiOx), silicon nitride (SiNx), silicon nitriding (SiON), or a so-called low-k material.
  • the photodetector 800B can electrically separate adjacent pixels by the pixel separation layer 850, so that crosstalk between pixels can be suppressed.
  • FIG. 119A is a plan view of the photodetector 800C according to the third variation as viewed from the second surface side.
  • FIG. 119B is a vertical cross-sectional view showing the structure of the photodetector 800C on the AA cut surface of FIG. 119A.
  • FIG. 119C is a vertical cross-sectional view showing the structure of the photodetector 800C on the B-BB cut surface of FIG. 119A.
  • the photodetector 800C provides the first conductive region 895, the overflow gate OFG, the overflow drain OFD, and the discharge electrode 897 with respect to the photodetector 800B according to the second variation. Furthermore, the points to be prepared are different.
  • the photodetector 800C can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 120A is a plan view of the photodetector 800D according to the fourth variation as viewed from the second surface side.
  • FIG. 120B is a vertical cross-sectional view showing the structure of the photodetector 800D on the AA cut surface of FIG. 120A.
  • FIG. 120C is a vertical cross-sectional view showing the structure of the photodetector 800D on the B-BB cut surface of FIG. 120A.
  • the photodetector 800D is different from the photodetector 800B described in FIGS. 118A to 118C in that the metal layer 852 is further provided inside the pixel separation layer 850.
  • the metal layer 852 is made of a light-shielding metal and is provided inside the pixel separation layer 850. Specifically, the metal layer 852 is provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and the side surface and the bottom surface are covered with the pixel separation layer 850. Since the metal layer 852 has a light-shielding property, it is possible to prevent light incident on the photodetector 800D from an oblique direction from entering adjacent pixels.
  • the metal layer 852 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
  • the photodetector 800D can prevent light from entering between pixels by the metal layer 852, so that crosstalk between pixels can be further suppressed.
  • FIG. 121A is a plan view of the photodetector 800E according to the fifth variation as viewed from the second surface side.
  • FIG. 121B is a vertical cross-sectional view showing the structure of the photodetector 800E on the AA cut surface of FIG. 121A.
  • FIG. 121C is a vertical cross-sectional view showing the structure of the photodetector 800E on the B-BB cut surface of FIG. 121A.
  • the photodetector 800E has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and an discharge electrode 897 with respect to the photodetector 800D according to the fourth variation. Furthermore, the point that it is provided is different.
  • the photodetector 800E can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 122A is a plan view of the photodetector 800F according to the sixth variation as viewed from the second surface side.
  • FIG. 122B is a vertical cross-sectional view showing the structure of the photodetector 800F on the AA cut surface of FIG. 122A.
  • FIG. 122C is a vertical cross-sectional view showing the structure of the photodetector 800F on the B-BB cut surface of FIG. 122A.
  • the photodetector 800F is different from the photodetector 800 described with reference to FIGS. 108A to 108C in that the control gate CG is provided in a vertical gate structure.
  • the control gate CG may be composed of a digging electrode 865 and a gate insulating film 863.
  • the digging electrode 865 may be provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and a gate insulating film 863 may be provided on the side surface and the bottom surface of the digging electrode 865.
  • the digging electrode 865 may be provided in a rectangular shape in the in-plane direction of the semiconductor substrate.
  • the photodetector 800F can further improve the controllability of the potential barrier generated in the region adjacent to the second region 820 during the DPD operation, and thus further improve the detection characteristics of the incident light. be able to.
  • FIG. 123A is a plan view of the photodetector 800G according to the seventh variation as viewed from the second surface side.
  • FIG. 123B is a vertical cross-sectional view showing the structure of the photodetector 800G on the AA cut surface of FIG. 123A.
  • FIG. 123C is a vertical cross-sectional view showing the structure of the photodetector 800G on the B-BB cut surface of FIG. 123A.
  • the photodetector 800G has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and an discharge electrode 897 with respect to the photodetector 800F according to the sixth variation. Furthermore, the point that it is provided is different.
  • the photodetector 800G can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 124A is a plan view of the photodetector 800H according to the eighth variation as viewed from the second surface side.
  • FIG. 124B is a vertical cross-sectional view showing the structure of the photodetector 800H on the AA cut surface of FIG. 124A.
  • FIG. 124C is a vertical cross-sectional view showing the structure of the photodetector 800H on the B-BB cut surface of FIG. 124A.
  • the light detection device 800H has, for example, a first region 810, a second region 820, a third region 830, a first electrode 811, a via 812, and a first surface insulation.
  • a gate insulating film 894, a floating diffusion FD, and an extraction electrode 893 are provided.
  • the first region 810 is a first conductive type region (for example, N + layer) provided on the first surface side of the semiconductor substrate.
  • the second region 820 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate.
  • the third region 830 is a third conductive type region (for example, i-layer or N-layer) provided between the first region 810 and the second region 820 of the semiconductor substrate.
  • the first electrode 811 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 851, and is electrically connected to the first region 810 via a via 812 or the like penetrating the first surface insulating layer 851. Connecting.
  • the first electrode 811 functions as, for example, a cathode electrode.
  • the first electrode 811 is provided so as to straddle the pixel separation layer 850 provided at the boundary between pixels, and is electrically connected to the first region 810 of each pixel by a via 812 provided for each pixel. As a result, the first electrode 811 can supply a common potential to the first region 810 of each pixel electrically separated by the pixel separation layer 850.
  • the pixel separation layer 850 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other.
  • the pixel separation layer 850 may be provided, for example, in a grid pattern along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
  • the metal layer 852 is made of a light-shielding metal and is provided inside the pixel separation layer 850. Specifically, the metal layer 852 is provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and the side surface and the bottom surface are covered with the pixel separation layer 850. The metal layer 852 can prevent light incident from an oblique direction from entering adjacent pixels.
  • the metal layer 852 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
  • the second electrode 821 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 820.
  • the second electrode 821 functions as, for example, an anode electrode.
  • the control gate 861 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 862.
  • the control gate 861 can control the potential barrier in the third region 830 by applying a voltage.
  • the first conductive type region 891 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate.
  • the first conductive region 891 is provided, for example, so that the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830.
  • the first conductive type region 891 is provided so as to extend in one direction from the second region 820.
  • the floating diffusion FD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate.
  • the floating diffusion FD may be provided inside the first conductive type region 891 on the end side of the first conductive type region 891 extending from the second region 820.
  • the transfer gate 892 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 894.
  • the transfer gate 892 is provided on the first conductive region 891 between the second region 820 and the floating diffusion FD, and can transfer charges from the second region 820 to the floating diffusion FD by applying a voltage.
  • the take-out electrode 893 is provided on the first surface of the semiconductor substrate and is electrically connected to the floating diffusion FD.
  • the take-out electrode 893 can output the electric charge accumulated in the floating diffusion FD to a pixel circuit or the like.
  • the pixel transistor region Tr is an region in which at least one or more of the pixel transistors included in the pixel circuit are provided.
  • the first electrode 811, via 812, second electrode 821, control gate 861, transfer gate 892, and take-out electrode 893 may be, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or It may be provided by a metal such as tantalum (Ta), polysilicon (poly-Si), or other conductive material.
  • the first surface insulating layer 851, the pixel separation layer 850, and the gate insulating films 862 and 894 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. It may be provided with an insulator.
  • the photodetector 800H has a so-called back-illuminated structure. As a result, the photodetector 800H can improve the light detection efficiency. Further, the photodetector 800H can improve the separability between pixels and the optical crosstalk characteristics between pixels by providing the pixel separation layer 850 and the metal layer 852.
  • FIG. 125A is a plan view of the photodetector 800I according to the ninth variation as viewed from the second surface side.
  • FIG. 125B is a vertical cross-sectional view showing the structure of the photodetector 800I on the AA cut surface of FIG. 125A.
  • FIG. 125C is a vertical cross-sectional view showing the structure of the photodetector 800I on the B-BB cut surface of FIG. 125A.
  • the photodetector 800I has a first conductive region 895, an overflow gate 896, a gate insulating film 898, and an overflow drain OFD, with respect to the photodetector 800H according to the eighth variation. And the discharge electrode 897 is further provided.
  • the photodetector 800I can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 126A is a plan view seen from the second surface side showing the structure of the photodetector 800J according to the tenth variation.
  • FIG. 126B is a vertical cross-sectional view showing the structure of the photodetector 800J on the AA cut surface of FIG. 126A.
  • FIG. 126C is a vertical cross-sectional view showing the structure of the photodetector 800J on the B-BB cut surface of FIG. 126A.
  • the photodetector 800J has a side wall electrode 853 in which the first region 810 is provided inside the pixel separation layer 850 with respect to the photodetector 800H according to the eighth variation. The difference is that they are electrically connected and only the first surface insulating layer 851 is provided on the first surface of the semiconductor substrate.
  • the side wall electrode 853 is provided so as to have a step in the thickness direction of the semiconductor substrate.
  • the first region 810 is provided in a shape in which one side of a rectangular shape is open along the first surface of the semiconductor substrate and the side surface of the pixel separation layer 850.
  • the side wall electrode 853 can be electrically connected to the first region 810 at the bottom surface of the step formed in the thickness direction of the semiconductor substrate.
  • the photodetector 800J can be electrically connected to the first region 810 without providing an electrode or wiring on the first surface of the semiconductor substrate, so that the aperture ratio is further increased. be able to. Therefore, the photodetector 800J can further improve the light detection efficiency.
  • FIG. 127A is a plan view seen from the second surface side showing the structure of the photodetector 800K according to the eleventh variation.
  • FIG. 127B is a vertical cross-sectional view showing the structure of the photodetector 800K on the AA cut surface of FIG. 127A.
  • FIG. 127C is a vertical cross-sectional view showing the structure of the photodetector 800K on the B-BB cut surface of FIG. 127A.
  • the photodetector 800K has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and a discharge electrode 897 with respect to the photodetector 800J according to the tenth variation. Furthermore, the point that it is provided is different.
  • the photodetector 800K can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
  • FIG. 128 is a schematic diagram showing an example of a planar configuration of a pixel array in which a plurality of pixels are arranged in a matrix.
  • FIG. 129 is a conceptual diagram illustrating switching between the DPD operation and the PD operation of the photodetector 800 according to the present embodiment.
  • FIG. 130 is a flowchart showing an example of a flow of switching between the DPD operation and the PD operation of the photodetector 800 according to the present embodiment.
  • the photodetector 800 includes a ToF pixel P ToF that acquires ToF information by a DPD operation and an imaging pixel Pimg that acquires imaging information by a PD operation in a pixel array. May be included respectively.
  • the ToF pixels P ToF may be periodically arranged in the pixel array at predetermined intervals from each other.
  • ToF pixel P ToF, and imaging pixel P img may be built in advance pixel array as a pixel to achieve the different functions.
  • each pixel in the pixel array may be selectively switched between operating as a ToF pixel P ToF or operating as an imaging pixel Pimg .
  • each pixel in the pixel array of the photodetector 800 can be acquired by switching the imaging information and the ToF information by switching between the DPD operation and the PD operation. You may be.
  • the photodetector 800 may acquire imaging information and ToF information by switching the operation mode of each pixel for each frame.
  • the photodetector 800 may acquire imaging information and ToF information by switching between a frame that performs a DPD operation and a frame that performs a PD operation for sensing.
  • the photodetector 800 may switch the operation mode for all pixels at once, or may selectively switch the operation mode for a specific pixel.
  • FIG. 130 is a flowchart illustrating an operation flow when switching between a DPD operation and a PD operation of the photodetector 800 according to the present embodiment.
  • the DPD operation and the PD operation are switched based on the high and low illuminance.
  • a threshold value for switching between the DPD operation and the PD operation is set in advance (S101).
  • the threshold value is set for a parameter related to illuminance.
  • the photon count control circuit is controlled to the ON state in order to perform the DPD operation (S102). Subsequently, after resetting the state of the light detection device 800 (S103), a reverse bias is applied to the light detection device 800, and then the bias is reversed from the reverse bias to the forward bias (S104). As a result, the optical signal is detected by the photodetector 800 (S105).
  • the number of output pulses is counted (S106), and the count value is output to the signal processing circuit (S107).
  • the signal processing circuit calculates the average of the count values of the specific pixels (S108). Further, it is determined whether or not the average of the calculated count values is larger than the preset threshold value (S109). When the average of the calculated count values is equal to or less than the threshold value (S109 / No), the processing flow returns to S102, and the photodetector 800 continues to execute the DPD operation.
  • the processing flow moves to S301 and the photon count control circuit is controlled to the off state (S301). Further, in order to perform the PD operation in the photodetector 800, the storage photodiode control circuit is controlled to be in the ON state (S201). Subsequently, after resetting the state of the photodetector 800 (S202), a reverse bias is applied to the photodetector 800 (S203). As a result, the electric charge converted by photoelectric in the photodetector 800 is accumulated (S204). After that, the accumulated charge is transferred to the floating diffusion FD (S205), and an optical signal is output (S206).
  • the processing flow determines whether or not the output voltage of the output optical signal is smaller than the threshold value (S207).
  • the processing flow returns to S201, and the photodetector 800 continues to execute the PD operation.
  • the processing flow moves to S302, and the storage photodiode control circuit is controlled to the off state (S302). Further, in order to perform the DPD operation in the photodetector 800, the photon count control circuit is controlled to the ON state (S102).
  • the photodetector 800 can perform photon counting by the DPD operation in the case of low illuminance, and can perform imaging by the PD operation in the case of high illuminance. According to this, the photodetector 800 can improve the S / N by performing photon counting by the DPD operation in low illuminance, and can suppress power consumption by performing imaging by the storage type PD operation in high illuminance. ..
  • the threshold value for switching between the DPD operation and the storage type PD operation may be set to a value at which a remarkable deterioration of S / N is observed in the storage type PD operation, for example.
  • the threshold value for switching between the DPD operation and the storage type PD operation may be set to a value in which the number of detected photons per frame is on the level of several hundreds.
  • the photodetector 800 may be controlled to perform photon counting by the PDP operation if the number of detected photons is smaller than the threshold value, and to perform imaging by the storage type PD operation if the number of detected photons is large.
  • FIG. 131 is a block diagram showing an outline of the photon counting operation by DPD.
  • FIG. 132 is a graph showing the correspondence between the photon incident on the DPD and the detected signal.
  • the counter circuit can generate a counter signal according to the number of received light pulses by counting the received light pulses.
  • the counter signal is information having an intensity corresponding to the number of photons.
  • the image processing circuit can acquire image information by signal processing the generated counter signal.
  • FIGS. 133 to 134C an example of a photon counting operation when the photodetector 800 according to the present embodiment is configured as a DPD capable of detecting one photon incident will be described.
  • FIG. 133 is a timing chart showing an example of the photon counting operation of the photodetector 800 according to the present embodiment.
  • FIG. 134A is a vertical cross-sectional view illustrating the state of the photodetector 800 at the timing of FIG. 133 (1)
  • FIG. 134B describes the state of the photodetector 800 at the timing of FIG. 133 (2). It is a vertical cross-sectional view
  • FIG. 134C is a vertical cross-sectional view illustrating a state of the photodetector 800 at the timing of FIG. 133 (3).
  • a positive voltage is applied to the voltage V SW applied to the gate of the switch transistor SW to turn on the switch transistor SW.
  • the voltage Va applied to the second electrode 821 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800.
  • the voltage V con applied to the control gate CG is set to a negative voltage (for example, -1V).
  • the photodetector 800 is set to a positive voltage (for example, + 1V) by setting the voltage Va applied to the second electrode 821 at the timing of (2) in FIG. 133.
  • a forward bias is applied between the first region 810 and the second region 820.
  • the voltage V con applied to the control gate CG is set to a positive voltage (for example, + 1V).
  • the photodetector 800 can detect one photon incident by the photon counting operation by DPD.
  • the voltage Va applied to the second electrode 821 at the timing of (3) in FIG. 133 is set to a negative voltage (for example, -1V).
  • a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800, so that the state of the photodetector 800 is reset.
  • the voltage V con applied to the control gate CG may also be set to a negative voltage (for example, -1V).
  • the photodetector 800 can perform the photon counting operation by DPD.
  • FIG. 135 is a block diagram showing a functional configuration when the photodetector 800 according to the present embodiment is applied to the pixel array that executes the photon counting operation.
  • a DPD control circuit 801 and a DPD signal detection circuit 803, a PD control circuit 802, a PD signal detection circuit 804, and a counter circuit 805 are connected to the photoelectric conversion unit DPD / PD of each pixel.
  • the DPD control circuit 801 and the DPD signal detection circuit 803 and the counter circuit 805 of each pixel are connected to the DPD horizontal control unit 8210, the DPD signal processing unit 8220, and the vertical control unit 8300. Further, the PD control circuit 802 and the PD signal detection circuit 804 of each pixel are connected to the PD horizontal control unit 8110, the PD signal processing unit 8120, and the vertical control unit 8300. Further, each pixel is connected to the DPD / PD switching control unit 8400 that switches the DPD operation or the PD operation of the photoelectric conversion unit DPD / PD.
  • the DPD / PD switching control unit 8400 is connected to the DPD horizontal control unit 8210, the PD horizontal control unit 8110, and each pixel.
  • the DPD / PD switching control unit 8400 switches the DPD / PD operation of each pixel by outputting the DPD / PD switching signal.
  • the DPD / PD operation switching may be performed for all pixels at once or for each predetermined pixel of the pixel array, depending on the application. Further, the switching of the DPD / PD operation may be performed by dividing the time, or may be performed for each frame.
  • the vertical control unit 8300 is connected to the DPD horizontal control unit 8210 and the PD horizontal control unit 8110, and when the DPD operation and the PD operation are performed by the photoelectric conversion unit DPD / PD, the DPD horizontal control unit 8210 and the PD horizontal control unit 8300 are controlled.
  • a read signal is output to unit 8110 line by line.
  • the DPD horizontal control unit 8210 reads the DPD signal of each pixel for each column and outputs the read DPD signal to the DPD signal processing unit 8220.
  • the DPD signal processing unit 8220 processes the input DPD signal and then outputs the signal-processed DPD signal as photon count data.
  • the PD horizontal control unit 8110 reads the PD signal of each pixel for each column and outputs the read PD signal to the PD signal processing unit 8120.
  • the PD signal processing unit 8120 processes the input PD signal and then outputs the processed PD signal as image data.
  • the photodetector 800 is used not only as an image sensor using PD operation and a ToF sensor using DPD operation, but also as a photon counter using DPD operation. It is possible.
  • FIG. 136 is a vertical cross-sectional view showing the structure of the photodetector 900 according to the present embodiment.
  • FIG. 137 is a graph diagram for explaining the variation in the time response of the current output from the photodetector 900
  • FIG. 138 is a graph diagram showing the deviation in linearity with respect to the variation in the time response shown in FIG. 137.
  • FIG. 139 is a plan view showing a pixel array configuration of the photodetector 900 according to the present embodiment.
  • FIG. 140 is a graph showing the relationship between the output of the normal pixel NP and the output of the reference pixel OBP in the pixel array shown in FIG. 139.
  • the photodetector 900 includes, for example, a first region 910, a second region 920, a third region 930, a control gate 963, and a gate insulating film 964.
  • the first region 910 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si).
  • the second region 920 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
  • the third region 930 is a third conductive type region (for example, layer i) provided between the first region 910 and the second region 920 of a semiconductor substrate such as silicon (Si).
  • the first region 910 is electrically connected to, for example, a first electrode (not shown) provided on the first surface of the semiconductor substrate.
  • the first electrode functions as, for example, a cathode electrode.
  • the second region 920 is electrically connected to a second electrode (not shown) provided on the second surface of the semiconductor substrate.
  • the second electrode functions as, for example, an anode electrode.
  • the control gate 963 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 964.
  • the control gate 963 can control the potential barrier in the third region 930 by applying a voltage.
  • the photodetector 900 outputs the magnitude of the incident light amount as the magnitude of the delay in the rise time of the forward current when the polarity of the bias is reversed from the reverse bias to the forward bias.
  • the photodetector 900 is configured as a pixel array in which a plurality of pixels are arranged, the amount of incident light and the forward current in each pixel are caused by a local temperature change in the pixel array or a deviation in the profile of each pixel. There may be variations in the relationship with the delay characteristics of.
  • the rising time of the forward current after reversing the polarity of the bias from the reverse bias to the forward bias may vary from pixel to pixel in the pixel array.
  • the rising time of the forward current after reversing the polarity of the bias from the reverse bias to the forward bias may vary from pixel to pixel in the pixel array.
  • FIG. 138 depending on the pixel, there may be a deviation in the linearity between the amount of incident light and the delay time for the rise of the forward current.
  • a different offset may occur in the relationship between the amount of incident light and the delay time for the rise of the forward current.
  • a reference pixel OBP is provided in the pixel array adjacent to the normal pixel NP.
  • a normal pixel NP is a pixel that photoelectrically converts incident light and emits an output according to the incident light.
  • the reference pixel OBP is a pixel that is provided with a light-shielding portion that blocks the incident light on the incident surface of the incident light and emits an output that does not depend on the incident light.
  • the reference pixel OBP is also referred to as an optical black pixel.
  • the photodetector 900 calculates the delay of the rising time of the forward current in the normal pixel NP with reference to the rising time of the forward current in the reference pixel OBP, so that the forward current corresponds to the amount of incident light. It is possible to detect the delay of the rising time of the above with higher accuracy. Further, in the photodetector 900 according to the present embodiment, since the reference pixel OBP is provided adjacent to the normal pixel NP, the influence of variation due to local temperature change in the pixel array, deviation of the profile of each pixel, or the like. Can be further suppressed. For example, the reference pixel OBP may be provided along the outer edge of the normal pixels NP arranged in a matrix as shown in FIG. 139.
  • the photodetector 900 it is possible to suppress variations in the output of each pixel in a pixel array in which a plurality of pixels are arranged, so that the amount of incident light can be detected with higher accuracy. Can be done.
  • FIG. 141 is a schematic plan view illustrating a first variation of the plane arrangement of the normal pixel NP and the reference pixel OBP.
  • FIG. 142 is a vertical cross-sectional view showing a cross-sectional structure of the AA cut surface of FIG. 141.
  • the normal pixel NP and the reference pixel OBP may be arranged in a checkered grid pattern (checkered flag pattern pattern) in the pixel array.
  • the normal pixel NP and the reference pixel OBP may be arranged alternately in the row direction and the column direction of the matrix array.
  • the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are separated from each other, respectively.
  • the two regions 920 and the third region 930 are similarly provided.
  • the reference pixel OBP is provided with, for example, a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910. As a result, the incident light on the third region 930 is blocked, so that the reference pixel OBP can emit an output that does not depend on the incident light.
  • the output from the normal pixel NP and the reference pixel OBP is input to the output circuit Out.
  • the output circuit Out can detect the delay of the rising time of the forward current in the normal pixel NP with higher accuracy by using the rising time of the forward current in the adjacent reference pixel OBP as a reference.
  • the normal pixel NP and the reference pixel OBP are alternately arranged in the pixel array, the influence of the variation in the in-plane direction in the pixel array can be further suppressed.
  • FIG. 143 is a schematic plan view illustrating a second variation of the plane arrangement of the normal pixel NP and the reference pixel OBP.
  • FIG. 144 is a vertical cross-sectional view showing a cross-sectional structure of the B-BB cut surface of FIG. 143.
  • the normal pixel NP and the reference pixel OBP may be provided in different plane areas in the pixel array.
  • the reference pixel OBP may be provided with a plane area smaller than that of the normal pixel NP.
  • the normal pixel NP and the reference pixel OBP are continuously arranged in the first direction of the matrix array (column direction in FIG. 143), and are arranged in the second direction orthogonal to the first direction of the matrix array (row direction in FIG. 143). May be alternately arranged in.
  • the reference pixel OBP may be provided in a plane area smaller than that of the normal pixel NP by being provided with a width smaller than that of the normal pixel NP in the second direction (row direction in FIG. 143).
  • the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are separated from each other, respectively. It includes two regions 920 (second regions 920N, 920B) and a third region 930. Further, the reference pixel OBP further includes a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910.
  • the second region 920N of the normal pixel NP and the second region 920B of the reference pixel OBP are provided so as to have the same size.
  • the size of the second regions 920N and 920B from which the output to the output circuit Out is taken out is a main factor for determining the rise time of the forward current. Therefore, the normal pixel NP and the reference pixel OBP have the same size of the second regions 920N and 920B, so that the reference of the rising time of the forward current can be aligned. According to this, the output circuit Out can detect the delay of the rising time of the forward current in the normal pixel NP with reference to the rising time of the forward current in the reference pixel OBP.
  • the aperture ratio in the pixel array can be improved by making the plane area of the reference pixel OBP including the light-shielding portion BM smaller than the plane area of the normal pixel NP in the pixel array. ..
  • FIG. 145 is a schematic plan view illustrating a third variation of the plane arrangement of the normal pixel NP and the reference pixel OBP.
  • FIG. 146 is a vertical cross-sectional view showing a cross-sectional structure of the C-CC cut surface of FIG. 145.
  • the reference pixel OBP may be provided for each of a plurality of normal pixel NPs in the pixel array.
  • the reference pixel OBP may be periodically provided at a ratio of 1 to 3 normal pixels NP.
  • the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are respectively separated. It includes two regions 920 and a third region 930.
  • the reference pixel OBP further includes, for example, a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910. As a result, the incident light on the third region 930 is blocked, so that the reference pixel OBP can emit an output that does not depend on the incident light.
  • the ratio of the reference pixel OBP provided with the light-shielding portion BM to the normal pixel NP can be reduced in the pixel array, so that the aperture ratio in the pixel array can be improved. Even in such a case, the photodetector 900 can sufficiently suppress the influence of the variation in the in-plane direction in the pixel array.
  • FIG. 147 is a schematic plan view illustrating a fourth variation of the plane arrangement of the normal pixel NP and the reference pixel OBP.
  • the reference pixel OBP may be periodically provided in the pixel array in which the normal pixel NPs are arranged in a matrix.
  • the reference pixel OBP may be periodically provided at a ratio of 1 in a pixel group of 8 rows ⁇ 8 columns.
  • the photodetector 900 monitors the rising time of the forward current from each reference pixel OBP during operation.
  • the photodetector 900 may, for example, correct or calibrate the output from the reference pixel OBP based on the monitoring results, or raise an alert based on a predetermined criterion.
  • the ratio of the reference pixel OBP provided with the light-shielding portion BM to the normal pixel NP can be reduced in the pixel array, so that the aperture ratio in the pixel array can be improved. Even in such a case, the photodetector 900 can sufficiently suppress the influence of the variation in the in-plane direction in the pixel array.
  • FIG. 148 is a vertical cross-sectional view showing a fifth variation of the cross-sectional configuration of the normal pixel NP and the reference pixel OBP.
  • FIG. 149 is a graph showing the correspondence between the opening area of the reference pixel OBP and the delay time for the rise of the forward current.
  • each of the reference pixels OBP provided in the pixel array may be provided so that the areas of the light-shielding portions BM provided on the incident surface of the light are different from each other.
  • the areas of the light-shielding portions BM1, BM2, BM3, BM4, BM5, and BM6 may be provided so as to be smaller in this order.
  • the photodetector 900 can create a calibration curve showing the correspondence between the change in the opening area due to the light-shielding portion BM and the delay time for the rise of the forward current. Therefore, the photodetector 900 simply creates the calibration curve for each amount of incident light to easily confirm the delay time of the rise of the forward current when one photon is incident, the dynamic lens for measurement, or the like. It is possible.
  • FIG. 150 is a block diagram showing a first circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
  • the normal pixel NP and the reference pixel OBP include a photoelectric conversion unit DPD / PD, a drive circuit 901, a waveform detection unit 902, and a counter 903.
  • the electric charge or current output from the photoelectric conversion unit DPD / PD is detected by the waveform detection unit 902 and then measured by the counter 903.
  • the drive circuit 901 controls the drive of the photoelectric conversion unit DPD / PD based on the electric charge or the current detected by the waveform detection unit 902.
  • the outputs of the normal pixel NP and the reference pixel OBP are read out under the control of the vertical control unit 9300 and the horizontal control unit 9010, respectively.
  • the read output is signal-processed by the signal processing unit 9020 and then output as an image output.
  • the reference pixel OBP may be arranged at the outer edge portion of the normal pixel NP.
  • FIG. 151 is a block diagram showing a second circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
  • the normal pixel NP and the reference pixel OBP include a photoelectric conversion unit DPD / PD, a drive circuit 901, a waveform detection unit 902, and a counter 903.
  • the electric charge or current output from the photoelectric conversion unit DPD / PD is detected by the waveform detection unit 902 and then measured by the counter 903.
  • the drive circuit 901 controls the drive of the photoelectric conversion unit DPD / PD based on the electric charge or the current detected by the waveform detection unit 902.
  • the outputs of the normal pixel NP and the reference pixel OBP are read out under the control of the vertical control unit 9300 and the horizontal control unit 9010, respectively.
  • the read output is signal-processed by the signal processing unit 9020 and then output as an image output.
  • the reference pixel OBP may be arranged inside the pixel array of the normal pixel NP.
  • FIG. 152 is a block diagram showing a third circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
  • the photodetector 900 may be configured as a pixel array in which normal pixels NP and reference pixels OBP have a one-to-one correspondence.
  • the normal pixel NP and the reference pixel OBP each include a photoelectric conversion unit DPD / PD, a drive circuit 901, and a waveform detection unit 902. Further, for each pair of the normal pixel NP and the reference pixel OBP, one counter 903 for measuring the incident photon based on the detection result of each waveform detection unit 902 of the normal pixel NP and the reference pixel OBP is provided.
  • the outputs of the normal pixel NP and the reference pixel OBP are read out for each pair of the normal pixel NP and the reference pixel OBP under the control of the vertical control unit 9300 and the horizontal control unit 9010.
  • the read output is signal-processed by the signal processing unit 9020 and then output as an image output.
  • the photodetector 900 can further improve the accuracy of the output from each of the normal pixel NPs by providing the normal pixel NP and the reference pixel OBP in a one-to-one correspondence. it can.
  • FIG. 153 is a block diagram showing a fourth circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
  • the photodetector 900 may further include a light source LD and a ToF light source control unit 9500, and may operate as a ToF sensor.
  • the ToF light source control unit 9500 is connected to the vertical control unit 9300 and the signal processing unit 9020, and controls the light emission timing of the light source LD during the ToF operation.
  • the signal processing unit 9020 can calculate the flight time of the light reflected by the object based on the light emission timing in the light source LD and the delay time of the output from the normal pixel NP, and can output the ToF output. Therefore, the photodetector 900 can also operate as a ToF sensor.
  • the above-mentioned photodetector may be provided in the laminated structure shown in FIG. 154.
  • the photodetector has a structure in which a light receiving chip 1100 that receives incident light and performs photoelectric conversion and a logic chip 1200 that performs arithmetic processing on the output from the light receiving chip 1100 are laminated. It may be provided at.
  • the light receiving chip 1100 and the logic chip 1200 may be electrically connected to each other by TSV (Through-Silicon Via) or so-called CuCu bonding.
  • the above-mentioned photodetector can be applied to a solid-state image sensor.
  • the solid-state image pickup device 1 using the above-mentioned photodetector may be provided with any of the substrate configurations A to C in FIG. 155.
  • FIG. 155A shows an example in which the solid-state image sensor 1 is composed of one semiconductor substrate 1110 and a support substrate 1210 laminated under the semiconductor substrate 1110.
  • the upper semiconductor substrate 1110 includes a pixel array region 1151 in which a plurality of pixels are arranged, a control circuit 1152 for controlling each pixel in the pixel array region 1151, and a logic circuit 1153 including a signal processing circuit for pixel signals. And are formed.
  • the control circuit 1152 includes a vertical control unit, a horizontal control unit, and the like.
  • the logic circuit 1153 includes a column processing unit that performs AD conversion processing of pixel signals, a distance calculation process that calculates a distance from the ratio of pixel signals output from each pixel in the pixel array region 1151, and a calibration process.
  • a signal processing unit to perform is included.
  • the solid-state image sensor 1 has a first semiconductor substrate 1120 on which the pixel array region 1151 and the control circuit 1152 are formed, and a second semiconductor substrate on which the logic circuit 1153 is formed. It is also possible to have a configuration in which 1220 and 1220 are laminated. The first semiconductor substrate 1120 and the second semiconductor substrate 1220 are electrically connected by, for example, a through via or a metal bond of Cu—Cu.
  • the solid-state image sensor 1 may have a configuration in which the first semiconductor substrate 1130 and the second semiconductor substrate 1230 are laminated.
  • the first semiconductor substrate 1130 is provided with only a pixel array region 1151
  • the second semiconductor substrate 1230 is provided with a control circuit for controlling each pixel and a signal processing circuit for processing a pixel signal in units of one pixel or a plurality of.
  • An area control circuit 1154 provided for each pixel area is provided.
  • the first semiconductor substrate 1130 and the second semiconductor substrate 1230 are electrically connected by, for example, through vias or metal bonds of Cu—Cu.
  • the control circuit and the signal processing circuit are provided for each pixel or area as in the solid-state image sensor 1 of C in FIG. And since the gain can be set, the optimized distance information can be acquired regardless of the distance or the reflectance. Further, since the solid-state image sensor 1 can drive only a part of the pixel array region 1151 instead of the entire surface to calculate the distance information, it is possible to suppress the power consumption according to the operation mode. Is.
  • the light receiving chip 1100 of the photodetector may include a pixel array region 1151 including light receiving elements 30 arranged in a plane in a matrix corresponding to the pixels.
  • the logic chip 1200 may include a pixel circuit area 1261 provided corresponding to the pixel array area 1151.
  • pixel circuits 1270 for controlling each of the pixels included in the pixel array area 1151 are provided in a planar arrangement in a matrix for each pixel.
  • Each of the pixel circuits 1270 is driven and controlled by a vertical control unit 1262 and a horizontal control unit 1263 provided around the pixel circuit area 1261.
  • the pixel signals read from each of the pixel circuits 1270 are signal-processed by the signal processing unit 1264 and output as image data to the outside.
  • the above-mentioned photodetector may be provided with the circuit configuration shown in FIG. 158.
  • each pixel in the pixel array includes, for example, a light receiving element 30 that can operate as a DPD, a drive circuit 1271, a waveform detection unit 1272, and a counter 1273.
  • the charge or current output from the light receiving element 30 is detected by the waveform detection unit 1272 and then measured by the counter 1273.
  • the counter 1273 has, for example, a function of detecting a "current rise time” in a ToF application and a function of detecting a "current rise count” in a photon counting application.
  • the drive circuit 1271 may control the drive of the light receiving element 30 based on the charge or the current detected by the waveform detection unit 1272.
  • the vertical control unit 1262 and the horizontal control unit 1263 read out the output from each pixel by controlling each pixel.
  • the read output is output as image data after signal processing by the signal processing unit 1264.
  • the above-mentioned photodetector can be applied to, for example, the solid-state image sensor 1010A shown in FIG. 159.
  • the solid-state image sensor 1010A has, for example, a structure in which a sensor substrate 1020 and a circuit board 1030 are vertically laminated.
  • the above-mentioned photodetector can be applied as, for example, a light receiving device of the sensor unit 1021.
  • the sensor board 1020 includes, for example, a sensor unit 1021 and a row selection unit 1025.
  • the sensor unit 1021 has a plurality of sensors 1040 arranged in a matrix.
  • the sensor 1040 includes, for example, a photodiode 1041, a transfer transistor (also referred to as a transfer gate) 1042, a reset transistor 1043, an amplification transistor 1044, a selection transistor 1045, and a stray diffusion region (FD) 1046.
  • the row selection unit 1025 selects each sensor 1040 of the sensor unit 1021 in units of rows based on the address signal given from the circuit board 1030 side. Although the row selection unit 1025 is provided on the sensor board 1020 here, it can also be provided on the circuit board 1030.
  • the circuit board 1030 includes, for example, a signal processing unit 1031, a memory unit 1032, a data processing unit 1033, a control unit 1034, a current source 1035, a decoder 1036, a row decoder 1037, an interface (IF) unit 1038, and the like.
  • a sensor drive unit (not shown) for driving each sensor 1040 of the sensor unit 1021 is provided.
  • the signal processing unit 1031 receives, for example, a predetermined signal including digitization (AD conversion) in parallel (column parallel) for each sensor row with respect to the analog signal read from each sensor 1040 of the sensor unit 1021 for each sensor row. Processing can be performed.
  • the signal processing unit 1031 has an analog-to-digital converter (AD converter) 1050 that digitizes the analog signal read from each sensor 1040 of the sensor unit 1021 to the signal line 1026, and is subjected to AD conversion.
  • the image data (digital data) is transferred to the memory unit 1032.
  • a row control line is wired for each sensor row and a column signal line (vertical signal line) is wired for each sensor row to the sensor unit 1021 in which the sensors 1040 are arranged in a matrix. There is.
  • the signal processing unit 1031 may further have a reference voltage generation unit 1054 that generates a reference voltage used for AD conversion by the AD converter 1050.
  • the reference voltage generation unit 1054 can be configured by using, for example, a DA converter (digital-analog converter), but is not limited thereto.
  • the AD converter 1050 has, for example, a comparator 1051 and a counter unit 1052.
  • the comparator 1051 compares both inputs using the analog signal read from each sensor 1040 of the sensor unit 1021 via the signal line 1026 as the comparison input and the reference voltage supplied from the reference voltage generation unit 1054 as the reference input.
  • an up / down counter is used as the counter unit 1052.
  • the clock CK is given to the counter unit 1052 at the same timing as the supply start timing of the reference voltage to the comparator 1051.
  • the counter unit 1052 which is an up / down counter, performs down-counting or up-counting in synchronization with the clock CK to perform a period of the pulse width of the output pulse of the comparator 1051 (that is, from the start of the comparison operation to the comparison operation). (Comparison period until the end) is measured. Then, the count result (count value) of the counter unit 1052 becomes a digital value (image data) obtained by digitizing the analog signal.
  • the data latch unit 1055 latches the image data digitized by the AD converter 1050.
  • the memory unit 1032 stores image data that has undergone predetermined signal processing in the signal processing unit 1031.
  • the data processing unit 1033 reads the image data stored in the memory unit 1032 in a predetermined order, performs various processes, and outputs the image data to the outside of the chip via the interface (IF) 1038.
  • the control unit 1034 is a sensor drive unit (not shown), a memory unit 1032, and a data processing unit based on reference signals such as a horizontal synchronization signal XHS, a vertical synchronization signal XVS, and a master clock MCK given from outside the chip. It controls each operation of the signal processing unit 1031 such as 1033. At this time, the control unit 1034 synchronizes the circuit on the sensor board 1020 side (row selection unit 1025 and sensor unit 1021) with the signal processing unit 1031 (memory unit 1032, data processing unit 1033, etc.) on the circuit board 1030 side. Control while taking.
  • the current source 1035 is connected to, for example, each of the signal lines 1026 from which analog signals are read out for each sensor row from each sensor 1040 of the sensor unit 1021.
  • the current source 1035 has, for example, a load MOS circuit configuration including a MOS transistor whose gate potential is biased to a constant potential so as to supply a predetermined current to the signal line 1026.
  • the current source 1035 including such a load MOS circuit operates the amplification transistor 1044 as a source follower by supplying a constant current to the amplification transistor 1044 of the sensor 1040 included in the selected row.
  • the decoder 1036 gives an address signal for designating the address of the selected row to the row selection unit 1025 when selecting each sensor 1040 of the sensor unit 1021 in line units based on the control of the control unit 1034.
  • the row decoder 1037 specifies a row address for writing image data to the memory unit 1032 and reading image data from the memory unit 1032 based on the control of the control unit 1034.
  • the sensor substrate 1020 and the circuit board 1030 are electrically connected via a connection portion such as a TSV (Through Silicon Via) that penetrates the semiconductor substrate.
  • a connection portion such as a TSV (Through Silicon Via) that penetrates the semiconductor substrate.
  • TSV Through Silicon Via
  • a so-called Twin TSV method in which two TSVs, a TSV provided on the sensor board 1020 and a TSV provided from the sensor board 1020 to the circuit board 1030, are connected on the outer surface of the chip, or
  • a so-called Shared TSV method or the like in which both are connected by a TSV penetrating from the sensor board 1020 to the circuit board 1030 can be used.
  • the sensor board 1020 and the circuit board 1030 are electrically connected via a connection portion such as a so-called metal joint in which electrode pads formed on the joint surfaces of each other are bonded to each other.
  • the electrode pad is made of a metal such as copper and is also called a Cu-Cu bond.
  • bump bonding or the like can be used for the connection portion between the sensor board 1020 and the circuit board 1030.
  • the solid-state image sensor to which the above-mentioned photodetector is applied may have, for example, the cross-sectional structure shown in FIGS. 160A and 160B.
  • FIG. 160A is an example of a cross-sectional configuration of an effective pixel
  • FIG. 160B is an example of a cross-sectional configuration of a light-shielding pixel.
  • the solid-state image sensor 1300 to which the photodetector is applied is provided with a laminated structure in which the lower substrate 1320 and the upper substrate 1310 are laminated.
  • the lower substrate 1320 and the upper substrate 1310 are electrically connected by a CuCu joint portion 1370 including a connection structure in which metal electrodes are bonded to each other.
  • the lower board 1320 includes a logic circuit such as a signal reading circuit and a signal processing circuit, and a circuit unit 1380 including a memory circuit.
  • the upper substrate 1310 includes a wiring portion 1360, a pixel portion 1350, a back surface electrode portion 1340, and a light incident portion 1330.
  • the upper substrate 1310 is provided by laminating the wiring portion 1360, the pixel portion 1350, the back surface electrode portion 1340, and the light incident portion 1330 in this order from the laminated surface side with the lower substrate 1320.
  • the wiring unit 1360 includes a wiring layer 1361 and an interlayer insulating film 1362.
  • the wiring unit 1360 transmits the output from each pixel included in the pixel unit 1350 to the circuit unit 1380 via the CuCu junction 1370.
  • the pixel unit 1350 electrically connects the first region 1351 of the first conductive type (N +), the second region 1352 of the second conductive type (P +), the third region 1353 of the third conductive type (i), and the pixels. Includes a pixel separation layer 1355 to separate into.
  • the pixel unit 1350 converts the light incident on the solid-state image sensor 1300 into a signal and outputs it to the wiring unit 1360.
  • the back electrode portion 1340 includes a first electrode 1342 electrically connected to the first region 1351 and an insulating film 1341 that embeds and flattens the first electrode 1342.
  • the first electrode 1342 is provided by opening the incident surface of the light of the pixel.
  • the first electrode 1342 covers the incident surface of the light of the pixel in order to block the light incident on the pixel. It is provided.
  • the light incident unit 1330 includes a color filter 1332 that controls the wavelength band of light incident on the pixel unit 1350 for each pixel, and an on-chip lens 1331 that collects the incident light at the center of the pixel.
  • the solid-state image sensor 1300 such as ToF or sensing, it may be arbitrarily selected whether or not the color filter 1332 and the on-chip lens 1331 are provided.
  • circuits included in the circuit unit 1380 may be provided on the upper board 1310. Alternatively, all the circuits included in the circuit unit 1380 may be provided on the same substrate as the pixel unit 1350. In such a case, the circuit unit 1380 is provided in the peripheral region of the pixel region in which the pixel unit 1350 is arranged.
  • FIG. 161 is a block diagram showing a configuration example of a distance image sensor which is an electronic device using a sensor chip using the above-mentioned photodetector.
  • the distance image sensor 2201 includes an optical system 2202, a sensor chip 2203, an image processing circuit 2204, a monitor 2205, and a memory 2206. Then, the distance image sensor 2201 receives the light (modulated light or pulsed light) reflected on the surface of the subject after the light is projected from the light source device 2211 toward the subject, so that the distance to the subject corresponds to the distance. Images can be acquired.
  • the optical system 2202 is configured to have one or a plurality of lenses, guides the image light (incident light) from the subject to the sensor chip 2203, and forms an image on the light receiving surface (sensor unit) of the sensor chip 2203.
  • the above-mentioned photodetector can be applied to the sensor chip 2203.
  • the distance signal indicating the distance obtained from the light receiving signal output from the sensor chip 2203 and the light emission timing signal output from the light source device 2211 are supplied to the image processing circuit 2204.
  • the image processing circuit 2204 performs image processing for constructing a distance image based on the light emission timing signal supplied from the light source device 2211 and the distance signal supplied from the sensor chip 2203.
  • the distance image (image data) obtained by the image processing is supplied to the monitor 2205 and displayed, or is supplied to the memory 2206 and stored (recorded).
  • the distance image sensor 2201 configured in this way, by applying the above-mentioned photodetector, for example, a more accurate distance image can be acquired as the characteristics of the DPD pixel are improved.
  • FIG. 162 is a block diagram showing a configuration example of a distance measuring module that outputs distance measurement information using a photodetector.
  • the ranging module 1000 includes a light emitting unit 1011, a light emitting control unit 1012, and a light receiving unit 1013.
  • the light emitting unit 1011 has a light source that emits light having a predetermined wavelength, and emits irradiation light whose brightness fluctuates periodically to irradiate an object.
  • the light emitting unit 1011 has a light emitting diode that emits infrared light having a wavelength in the range of 780 nm to 1000 nm as a light source, and emits light in synchronization with the light emission control signal CLKp of a square wave supplied from the light emitting control unit 1012. It emits light.
  • the emission control signal CLKp is not limited to a square wave as long as it is a periodic signal.
  • the light emission control signal CLKp may be a sine wave.
  • the light emission control unit 1012 supplies the light emission control signal CLKp to the light emitting unit 1011 and the light receiving unit 1013, and controls the irradiation timing of the irradiation light.
  • the frequency of the light emission control signal CLKp is, for example, 20 megahertz (MHz).
  • the frequency of the light emission control signal CLKp is not limited to 20 MHz (MHz) and may be 5 MHz (MHz) or the like.
  • the light receiving unit 1013 receives the reflected light reflected from the object, calculates the distance information for each pixel according to the light receiving result, and generates a depth image in which the distance to the object is represented by a gradation value for each pixel. Output.
  • the above-mentioned photodetector is used for the light receiving unit 1013, and the solid-state image sensor as the light receiving unit 1013 is, for example, a distance from the signal intensity detected in each pixel of the pixel array unit based on the light emission control signal CLKp. Information is calculated for each pixel.
  • the above-mentioned photodetector can be incorporated as the light receiving unit 1013 of the distance measuring module 1000 that obtains and outputs the distance information to the subject by, for example, the indirect ToF method.
  • the above-mentioned photodetector as the light receiving unit 1013 of the distance measuring module 1000, the distance measuring characteristics of the distance measuring module 1000 can be improved.
  • the distance measuring characteristics can be improved.
  • FIG. 163A shows the configuration of the photodetector 10 when electrons are used as the signal carrier
  • FIG. 163B shows the configuration of the photodetector 10A when holes are used as the signal carrier.
  • the photodetector 10 electrically includes, for example, an N + type first region 11, a P + type second region 12, an i-type third region 13, and a first region 11.
  • the second region 12 provided for detecting the signal carrier is configured as a P + type semiconductor region, and the first region 11 provided for generating an electric field in the substrate is provided. It is configured as an N + semiconductor region.
  • the photodetector 10 can detect electrons as signal carriers in the second region 12.
  • the photodetector 10A has, for example, a P + type first region 11A, an N + type second region 12A, an i type third region 13, and a first region 11 and electricity.
  • a control gate that controls the potential of the first electrode 21, the pixel separation layer 15 that separates the pixels, the second electrode 22 that is electrically connected to the second region 12, and the third region 13. 25 and a gate insulating film 26 are provided.
  • the second region 12A provided for detecting the signal carrier is configured as an N + type semiconductor region, and the first region 11A provided for generating an electric field in the substrate is provided. It is configured as a P + semiconductor region.
  • the photodetector 10A can detect holes as signal carriers in the second region 12A.
  • the technology according to the present disclosure relates to semiconductor devices such as image sensors that can be used for both imaging and sensing.
  • the present invention relates to a photodetector capable of operating photon counting, ToF (Time-of-Flight), and the like.
  • the photodetector according to the present disclosure as a back-illuminated CMOS image sensor, it is possible to reduce the wiring on the light incident surface side and increase the aperture ratio of the light receiving portion. This improves the sensitivity of the sensor of the photodetector.
  • a charge detection unit (first region or second region, etc.) and a voltage application unit (cathode electrode or anode electrode) provided in the pixel are provided in the pixel depending on which characteristic such as the sensitivity of the pixel or the operation mode of the sensor is prioritized. Whether or not a part or all of the number and arrangement position, the shape and arrangement position of the charge detection unit, the anode electrode, the cathode electrode, the pixel transistor, the logic circuit unit, and the memory circuit unit are shared by a plurality of pixels.
  • Presence / absence of on-chip lens and color filter Presence / absence of on-chip lens and color filter, presence / absence of inter-pixel light-shielding part, presence / absence of separation area, shape and depth of inter-pixel light-shielding part or separation area, thickness of on-chip lens and substrate, substrate type and film design, It is possible to appropriately select various technical features such as the presence / absence of a bias on the incident surface and the presence / absence of a reflective member.
  • the technology according to the present disclosure can also have the following configuration.
  • the first electrode extends from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate and is electrically connected to the first region on the bottom surface to form a second electrode.
  • the electrodes can be electrically connected to the second region from the second surface side of the semiconductor substrate. Therefore, the photodetector according to the present embodiment can improve the aperture ratio of the light incident surface, so that the detection characteristics of the incident light can be improved.
  • the effect of the technique according to the present disclosure is not necessarily limited to the effects described herein, and may be any of the effects described in the present disclosure.
  • the photoelectric conversion unit The first region of the first conductive type provided on the first surface side of the semiconductor substrate and A second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and A first electrode extending from the second surface in the thickness direction of the semiconductor substrate and electrically connecting to the first region on the bottom surface, An insulating pixel separation layer provided on the side surface of the first electrode and A photodetector comprising a second electrode that is electrically connected to the second region from the second surface side.
  • the gate electrode is a vertical gate electrode provided by digging the semiconductor substrate in the thickness direction.
  • the first conductive type potential control region which is provided on the second surface side of the semiconductor substrate with the second region and an insulating layer interposed therebetween and can control the potential.
  • the second conductive type floating diffusion region provided on the second surface side of the semiconductor substrate, and the floating diffusion region.
  • (1) to (12) further including a transfer gate transistor provided between the second region and the floating diffusion region and controlling the transfer of electric charges from the second region to the floating diffusion region.
  • the photodetector according to any one of the above.
  • the second conductive type overflow / drain region provided on the side opposite to the floating diffusion region with the second region interposed therebetween.
  • the pinning layer is a chargeable layer or the second conductive type layer.
  • a fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
  • a fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
  • the plurality of photoelectric conversion units include the photoelectric conversion unit of a reference pixel provided with a light-shielding portion on the incident surface of the incident light, and the photoelectric conversion unit of a normal pixel not provided with the light-shielding portion.
  • An insulating pixel separation layer provided on each side surface of the third electrode and the fourth electrode, and The second conductive type potential control region that is electrically connected to the bottom surface of the third electrode exposed from the through insulating layer, and The first conductive type reset region that is electrically connected to the bottom surface of the fourth electrode exposed from the through insulating layer, and A first electrode that is electrically connected to the first region from the first surface side, A photodetector comprising a second electrode that is electrically connected to the second region from the second surface side.
  • the photoelectric conversion unit A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode, A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode. A fourth region of the first conductive type provided in contact with the second region in the depth direction of the semiconductor substrate, An insulating layer that surrounds the bonding surface between the second region and the fourth region in the in-plane direction of the semiconductor substrate. A third conductive type third region provided on the semiconductor substrate and absorbing incident light, A photodetector.
  • the photoelectric conversion unit A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode, A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
  • the fifth region of the second conductive type provided in contact with the first region and
  • the fourth region of the first conductive type provided in contact with the second region and A third conductive type third region provided in a region between the fourth region and the fifth region of the semiconductor substrate and absorbing incident light, and A photodetector.
  • the photoelectric conversion unit A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode, A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
  • a third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and A photodetector comprising a surface corresponding to the third region of the semiconductor substrate and a layer having a chargeability at an interface with an insulating material or a pinning layer provided as the second conductive type layer.
  • the photoelectric conversion unit A first conductive type region provided on the first surface side of the semiconductor substrate and electrically connected to the first electrode, A second conductive type second region provided on the second surface side of the semiconductor substrate opposite to the first surface and electrically connected to the second electrode.
  • a third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and The second conductive type floating diffusion region provided on the second surface side of the semiconductor substrate, and the floating diffusion region.
  • a photodetector comprising a transfer gate transistor provided between the second region and the floating diffusion region to control charge transfer from the second region to the floating diffusion region.
  • a plurality of photoelectric conversion units provided in a region between the first region and the second region of the semiconductor substrate and including a third conductive type third region that absorbs incident light are provided.
  • the plurality of photoelectric conversion units include the photoelectric conversion unit of a reference pixel provided with a light-shielding portion on the incident surface of the incident light, and the photoelectric conversion unit of a normal pixel not provided with the light-shielding portion.
  • the reference pixel is a photodetector provided adjacent to the normal pixel.

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Abstract

A light detection device comprising a plurality of photoelectric conversion units provided on a semiconductor substrate. The photoelectric conversion units comprise: a first region having a first conductivity type and provided on a first surface side of the semiconductor substrate; a second region having a second conductivity type and provided on a second surface side of the semiconductor substrate that is opposite to the first surface; a third region having a third conductivity type, provided in a region between the first region and the second region in the semiconductor substrate, and absorbing incident light; a first electrode extending from the second surface in the thickness direction of the semiconductor substrate and being electrically connected to the first region, on a bottom surface; an insulating pixel separation layer provided on a side surface of the first electrode; and a second electrode electrically connected to the second region from the second surface side.

Description

光検出装置Photodetector
　本開示は、光検出装置に関する。 This disclosure relates to a photodetector.
　近年、イメージング及びセンシングの両方の用途に用いることが可能な光検出装置が提案されている。具体的には、入射光量を電流又は電圧の動的な変化として検出する光検出装置が提案されている（例えば、特許文献１）。このような光検出装置は、フォトンカウントセンサ及びＴｏＦ（Ｔｉｍｅ　ｏｆ　Ｆｌｉｇｈｔ）センサ等として動作することが可能である。 In recent years, photodetectors that can be used for both imaging and sensing have been proposed. Specifically, a photodetector that detects the amount of incident light as a dynamic change in current or voltage has been proposed (for example, Patent Document 1). Such a photodetector can operate as a photon count sensor, a ToF (Time of Flight) sensor, or the like.
国際公開第２０１８／１６７５６７号International Publication No. 2018/167567
　このような光検出装置では、イメージセンサ等に適用された場合の具体的な構造について検討することが望まれている。例えば、複数の画素が行列状に配列された画素アレイに上記の光検出装置を適用した場合の構造について検討することが望まれている。 In such a photodetector, it is desired to study the specific structure when applied to an image sensor or the like. For example, it is desired to study the structure when the above-mentioned photodetector is applied to a pixel array in which a plurality of pixels are arranged in a matrix.
　よって、画素アレイにおける入射光の検出特性を向上させることが可能な光検出装置を提供することが望ましい。 Therefore, it is desirable to provide a photodetector capable of improving the detection characteristics of incident light in the pixel array.
　本開示の一実施形態に係る光検出装置は、半導体基板に設けられた複数の光電変換部を備え、前記光電変換部は、前記半導体基板の第１面側に設けられた第１導電型の第１領域と、前記半導体基板の前記第１面と反対の第２面側に設けられた第２導電型の第２領域と、前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、前記第２面から前記半導体基板の厚み方向に延在し、底面にて前記第１領域と電気的に接続する第１電極と、前記第１電極の側面に設けられた絶縁性の画素分離層と、前記第２面側から前記第２領域と電気的に接続する第２電極とを備える。 The optical detection device according to the embodiment of the present disclosure includes a plurality of photoelectric conversion units provided on the semiconductor substrate, and the photoelectric conversion units are of the first conductive type provided on the first surface side of the semiconductor substrate. Between the first region, the second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and the first region and the second region of the semiconductor substrate. A third conductive type third region that is provided in the region and absorbs incident light, extends from the second surface in the thickness direction of the semiconductor substrate, and is electrically connected to the first region at the bottom surface. It includes a first electrode, an insulating pixel separation layer provided on the side surface of the first electrode, and a second electrode that is electrically connected to the second region from the second surface side.
　本開示の一実施形態に係る光検出装置は、半導体基板の第１面側に設けられた第１導電型の第１領域、半導体基板の第１面と反対の第２面側に設けられた第２導電型の第２領域、及び第１領域と第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域を備える。本実施形態に係る光検出装置によれば、第１電極は半導体基板の第２面から半導体基板の厚み方向に延在して底面にて第１領域と電気的に接続し、第２電極は半導体基板の第２面側から第２領域と電気的に接続することができる。これにより、本実施形態に係る光検出装置は、例えば、第１電極又は第２電極と電気的に接続する配線層を光入射面と反対側の半導体基板の面に設けることができる。 The photodetector according to the embodiment of the present disclosure is provided in the first region of the first conductive type provided on the first surface side of the semiconductor substrate, and on the second surface side opposite to the first surface of the semiconductor substrate. It is provided in a second region of the second conductive type and a region between the first region and the second region, and includes a third region of the third conductive type that absorbs incident light. According to the optical detection device according to the present embodiment, the first electrode extends from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate and is electrically connected to the first region at the bottom surface, and the second electrode is It can be electrically connected to the second region from the second surface side of the semiconductor substrate. Thereby, in the photodetector according to the present embodiment, for example, a wiring layer electrically connected to the first electrode or the second electrode can be provided on the surface of the semiconductor substrate opposite to the light incident surface.
本開示の一実施形態に係る光検出装置の基本構成を模式的に示す説明図である。It is explanatory drawing which shows typically the basic structure of the photodetector which concerns on one Embodiment of this disclosure. 光検出装置の電流－電圧特性を示す模式的なグラフ図である。It is a schematic graph diagram which shows the current-voltage characteristic of a photodetector. 光検出装置に印加されるバイアス電圧の極性変化を示すグラフ図である。It is a graph which shows the polarity change of the bias voltage applied to the photodetector. バイアス電圧の極性変化に応じて光検出装置から流れる電流の遅延を示すグラフ図である。It is a graph which shows the delay of the current which flows from a photodetector according to the polarity change of a bias voltage. 光検出装置に入射する光と、バイアス電圧の変化に対する電流増加の遅延時間との関係の一例を示す模式的なグラフ図である。It is a schematic graph which shows an example of the relationship between the light incident on a photodetector, and the delay time of the current increase with respect to the change of a bias voltage. 光検出装置に入射する光と、バイアス電圧の変化に対する電流増加の遅延時間との関係の一例を示す模式的なグラフ図である。It is a schematic graph which shows an example of the relationship between the light incident on a photodetector, and the delay time of the current increase with respect to the change of a bias voltage. 光検出装置に入射する光と、バイアス電圧の変化に対する電流増加の遅延時間との関係の一例を示す模式的なグラフ図である。It is a schematic graph which shows an example of the relationship between the light incident on a photodetector, and the delay time of the current increase with respect to the change of a bias voltage. 光検出装置のより具体的な構成を示す縦断面図である。It is a vertical cross-sectional view which shows the more specific structure of a photodetector. バイアス電圧の変化に対する電流の変化を示すグラフ図である。It is a graph which shows the change of the current with respect to the change of a bias voltage. 図７の（１）のタイミングにおける光検出装置の電子及び正孔の動きを示す縦断面図である。It is a vertical cross-sectional view which shows the movement of the electron and hole of the photodetector at the timing of (1) of FIG. 図７の（２）のタイミングにおける光検出装置の電子及び正孔の動きを示す縦断面図である。It is a vertical cross-sectional view which shows the movement of the electron and the hole of the photodetector at the timing of (2) of FIG. 図７の（３）のタイミングにおける光検出装置の電子及び正孔の動きを示す縦断面図である。It is a vertical cross-sectional view which shows the movement of the electron and the hole of the photodetector at the timing of (3) of FIG. 図７の（４）のタイミングにおける光検出装置の電子及び正孔の動きを示す縦断面図である。It is a vertical cross-sectional view which shows the movement of the electron and the hole of the photodetector at the timing of (4) of FIG. 図７の（１）の各々のタイミングにおける光検出装置のＡ－ＡＡ切断面でのエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure at the AA cut surface of the photodetector at each timing of (1) of FIG. 図７の（２）の各々のタイミングにおける光検出装置のＡ－ＡＡ切断面でのエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure at the AA cut surface of the photodetector at each timing of (2) of FIG. 図７の（３）の各々のタイミングにおける光検出装置のＡ－ＡＡ切断面でのエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure at the AA cut surface of the photodetector at each timing of (3) of FIG. 図７の（４）の各々のタイミングにおける光検出装置のＡ－ＡＡ切断面でのエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure at the AA cut surface of the photodetector at each timing of (4) of FIG. 本開示の一実施形態に係る光検出装置の基本構造を示す縦断面図である。It is a vertical sectional view which shows the basic structure of the photodetector which concerns on one Embodiment of this disclosure. 同実施形態に係る光検出装置の基本構造を示す第１面側からの平面図である。It is a top view from the 1st surface side which shows the basic structure of the photodetector which concerns on this embodiment. 第１のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on the 1st variation. 第１のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 1st variation. 第２のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 2nd variation. 第３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 3rd variation. 第３のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 3rd variation. 第４のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 4th variation. 第５のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 5th variation. 第６のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 6th variation. 第６のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 6th variation. 第７のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 7th variation. 第８のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 8th variation. 第９のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 9th variation. 第１０のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on tenth variation. 図２１ＡのＡ－ＡＡ切断面における平面図である。It is a top view of the AA cut plane of FIG. 21A. 第１１のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on eleventh variation. 図２２ＡのＢ－ＢＢ切断面における平面図である。It is a top view of the B-BB cut plane of FIG. 22A. 第１２のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the twelfth variation. 第１３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 13th variation. 図２４ＡのＣ－ＣＣ切断面における平面図である。It is a top view of the C-CC cut plane of FIG. 24A. 第１４のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 14th variation. 第１５のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 15th variation. 第２領域及び第１電極の形成深さについて説明する縦断面図である。It is a vertical sectional view explaining the formation depth of a 2nd region and a 1st electrode. 同実施形態に係る光検出装置のＴｏＦセンサ動作の一例を示すタイミングチャート図である。It is a timing chart diagram which shows an example of the operation of the ToF sensor of the photodetector which concerns on this embodiment. ＴｏＦセンサに用いられる光源を説明する説明図である。It is explanatory drawing explaining the light source used for the ToF sensor. 図２８の（１）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (1) of FIG. 28. 図２８の（２）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (2) of FIG. 28. 図２８の（３）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (3) of FIG. 28. 第１の変形例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 1st modification. 第１の変形例に係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 1st modification. 第１の変形例に係る光検出装置における駆動電圧例を示すタイミングチャート図である。It is a timing chart figure which shows the driving voltage example in the photodetector which concerns on 1st modification. 第２の変形例に係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 2nd modification. 図３３ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 33A. 図３３ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 33A. ＤＰＤセンサ及びＰＤとして機能する光検出装置が備える画素回路の等価回路の一例を示す回路図である。It is a circuit diagram which shows an example of the equivalent circuit of the pixel circuit provided in the DPD sensor and the photodetector functioning as PD. 光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後の電荷の移動を時系列で示す模式図である。It is a schematic diagram which shows the movement of charge after reversing the bias applied to a photodetector from a reverse bias to a forward bias in chronological order. 検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後のバンド構造の変化を時系列で示すグラフ図である。It is a graph which shows the change of a band structure in time series after reversing the bias applied to a detection device from a reverse bias to a forward bias. 本開示の第２の実施形態に係る光検出装置の基本構造を示す縦断面図である。It is a vertical cross-sectional view which shows the basic structure of the photodetector which concerns on 2nd Embodiment of this disclosure. 同実施形態に係る光検出装置の基本構造を示す第１面側からの透過平面図である。It is a transmission plan view from the 1st surface side which shows the basic structure of the photodetector which concerns on this embodiment. 第１のバリエーションに係る光検出装置の構成を説明する第２面側から見た平面図である。It is a top view seen from the 2nd surface side explaining the structure of the photodetector device which concerns on 1st variation. 第２のバリエーションに係る光検出装置の構成を説明する第２面側から見た平面図である。It is a top view seen from the 2nd surface side explaining the structure of the photodetector device which concerns on 2nd variation. 第３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 3rd variation. 第４のバリエーションに係る光検出装置の構成を説明する第２面側から見た平面図である。It is a top view seen from the 2nd surface side explaining the structure of the photodetector device which concerns on 4th variation. 図４２のＡ－ＡＡ切断面における光検出装置の構成を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 42. 図４２のＢ－ＢＢ切断面における光検出装置の構成を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut surface of FIG. 42. 光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後の電荷の移動を時系列で示す模式図である。It is a schematic diagram which shows the movement of charge after reversing the bias applied to a photodetector from a reverse bias to a forward bias in chronological order. 光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後のエネルギーバンド構造の変化を時系列で示すグラフ図である。It is a graph which shows the change of the energy band structure in time series after reversing the bias applied to a photodetector from a reverse bias to a forward bias. 本開示の第３の実施形態に係る光検出装置の基本構造を示す縦断面図である。It is a vertical cross-sectional view which shows the basic structure of the photodetector which concerns on 3rd Embodiment of this disclosure. 第１のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on the 1st variation. 第２のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 2nd variation. 第３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 3rd variation. 第４のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 4th variation. 第５のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 5th variation. 第６のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 6th variation. 画素分離層、絶縁層、第２領域、及び第２電極の配置及び形状のバリエーションを説明する第２面側からの平面図である。It is a top view from the 2nd surface side explaining the variation of arrangement and shape of a pixel separation layer, an insulating layer, a 2nd region, and a 2nd electrode. 画素分離層、絶縁層、第２領域、及び第２電極の配置及び形状のバリエーションを説明する第２面側からの平面図である。It is a top view from the 2nd surface side explaining the variation of arrangement and shape of a pixel separation layer, an insulating layer, a 2nd region, and a 2nd electrode. 本開示の第４の実施形態に係る光検出装置の基本構造を示す縦断面図である。It is a vertical cross-sectional view which shows the basic structure of the photodetector which concerns on 4th Embodiment of this disclosure. 同実施形態に係る光検出装置のエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure of the photodetector which concerns on this embodiment. 同実施形態に係る光検出装置のエネルギーバンド構造を示すグラフ図である。It is a graph which shows the energy band structure of the photodetector which concerns on this embodiment. 第１のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on the 1st variation. 第１のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 1st variation. 第２のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 2nd variation. 第２のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 2nd variation. 第３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 3rd variation. 第３のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 3rd variation. 第４のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 4th variation. 、第４のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。, Is a plan view seen from the second surface side showing the structure of the photodetector according to the fourth variation. 第５のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 5th variation. 第６のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 6th variation. 第６のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 6th variation. 第７のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 7th variation. 第７のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 7th variation. 第８のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 8th variation. 第８のバリエーションに係る光検出装置の構造を示す第１面側から見た平面図である。It is a top view seen from the 1st surface side which shows the structure of the photodetector which concerns on 8th variation. 第９のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 9th variation. 第９のバリエーションに係る光検出装置の構造を示す第１面側から見た平面図である。It is a top view seen from the 1st surface side which shows the structure of the photodetector which concerns on 9th variation. 第１０のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on tenth variation. 第１１のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on eleventh variation. 第１１のバリエーションに係る光検出装置の構造を示す第１面側から見た平面図である。It is a top view seen from the 1st surface side which shows the structure of the photodetector which concerns on eleventh variation. 第１２のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the twelfth variation. 第１３のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 13th variation. 第１４のバリエーションに係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 14th variation. 第５の実施形態の第１の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 1st structural example of 5th Embodiment. 第１の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 1st structural example. 第１の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 1st structural example. 第２の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 2nd structural example. 第２の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 2nd structural example. 第２の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 2nd structural example. 第３の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 3rd structural example. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第４の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 4th structural example. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層７４１が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer 741 is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層７４１が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer 741 is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第５の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 5th structural example. 第６の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 6th structural example. 第７の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 7th structural example. 第８の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 8th structural example. 第９の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 9th structural example. 第１０の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on tenth structural example. 第１１の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on eleventh structural example. 第１２の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the twelfth structural example. 第１３の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 13th structural example. 第１３の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on 13th structural example. 第１３の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on 13th structural example. 第１４の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 14th structural example. 第１４の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 14th structural example. 第１４の構造例に係る光検出装置の平面構造の一例を示す上面図である。It is a top view which shows an example of the planar structure of the photodetector which concerns on the 14th structural example. 第１５の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on 15th structural example. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed on the surface side of the semiconductor layer including a 3rd region. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第１６の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 16th structural example. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図であるIt is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図であるIt is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 電荷生成層の表面側においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region where a pinning layer is formed on the surface side of a charge generation layer. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第３領域を含む半導体層と埋め込み絶縁膜との界面においてピニング層が形成される領域の一例を示す平面図である。It is a top view which shows an example of the region in which a pinning layer is formed at the interface between a semiconductor layer including a 3rd region and an embedded insulating film. 第１７の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector which concerns on the 17th structural example. 第１８の構造例に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 18th structural example. 本開示の第６の実施形態に係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 6th Embodiment of this disclosure. 図１０８ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 108A. 図１０８ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 108A. 光検出装置が備える画素回路に含まれる画素トランジスタの配置の一例を示す平面図である。It is a top view which shows an example of the arrangement of the pixel transistor included in the pixel circuit included in the photodetector. ＤＰＤセンサ及びＰＤとして機能する光検出装置が備える画素回路の等価回路の一例を示す回路図である。It is a circuit diagram which shows an example of the equivalent circuit of the pixel circuit provided in the DPD sensor and the photodetector functioning as PD. 同実施形態に係る光検出装置のＴｏＦセンサ動作の一例を示すタイミングチャート図である。It is a timing chart diagram which shows an example of the operation of the ToF sensor of the photodetector which concerns on this embodiment. ＴｏＦセンサに用いられる光源を説明する説明図である。It is explanatory drawing explaining the light source used for the ToF sensor. 図１１１の（１）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (1) of FIG. 111. 図１１１の（２）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (2) of FIG. 111. 図１１１の（３）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (3) of FIG. 111. 同実施形態に係る光検出装置のＰＤ動作の一例を示すタイミングチャート図である。It is a timing chart diagram which shows an example of PD operation of the photodetector which concerns on this embodiment. 図１１４の（１）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (1) of FIG. 114. 図１１４の（２）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (2) of FIG. 114. 図１１４の（３）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical sectional view explaining the state of the photodetector at the timing of (3) of FIG. 114. 図１１４の（４）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (4) of FIG. 114. 図１１４の（５）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (5) of FIG. 114. 同実施形態に係る光検出装置を画素アレイとした場合の機能構成を示すブロック図である。It is a block diagram which shows the functional structure when the photodetector which concerns on this embodiment is a pixel array. 第１のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 1st variation. 図１１７ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 117A. 図１１７ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 117A. 第２のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 2nd variation. 図１１８ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 118A. 図１１８ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 118A. 第３のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 3rd variation. 図１１９ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 119A. 図１１９ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 119A. 第４のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 4th variation. 図１２０ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 120A. 図１２０ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut surface of FIG. 120A. 第５のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 5th variation. 図１２１ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 121A. 図１２１ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical sectional view which shows the structure of the photodetector in the B-BB cut surface of FIG. 121A. 第６のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 6th variation. 図１２２ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 122A. 図１２２ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 122A. 第７のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 7th variation. 図１２３ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 123A. 図１２３ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 123A. 第８のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 8th variation. 図１２４ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 124A. 図１２４ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 124A. 第９のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 9th variation. 図１２５ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 125A. 図１２５ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 125A. 第１０のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on 10th variation. 図１２６ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 126A. 図１２６ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 126A. 第１１のバリエーションに係る光検出装置の構造を示す第２面側から見た平面図である。It is a top view seen from the 2nd surface side which shows the structure of the photodetector which concerns on eleventh variation. 図１２７ＡのＡ－ＡＡ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the AA cut surface of FIG. 127A. 図１２７ＡのＢ－ＢＢ切断面における光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector in the B-BB cut plane of FIG. 127A. 複数の画素が行列状に配列された画素アレイの平面構成の一例を示す模式図である。It is a schematic diagram which shows an example of the plane structure of the pixel array in which a plurality of pixels are arranged in a matrix. 同実施形態に係る光検出装置のＤＰＤ動作とＰＤ動作との切り替えを説明する概念図である。It is a conceptual diagram explaining the switching between the DPD operation and the PD operation of the photodetector which concerns on this embodiment. 同実施形態に係る光検出装置のＤＰＤ動作とＰＤ動作との切り替えの流れの一例を示すフローチャート図である。It is a flowchart which shows an example of the flow of switching between the DPD operation and the PD operation of the photodetector which concerns on this embodiment. ＤＰＤによるフォトンカウント動作の概要を示すブロック図である。It is a block diagram which shows the outline of the photon count operation by DPD. ＤＰＤに入射した光子と、検出される信号との対応関係を示すグラフ図である。It is a graph which shows the correspondence relationship between a photon incident on a DPD and a detected signal. 同実施形態に係る光検出装置のフォトンカウント動作の一例を示すタイミングチャート図である。It is a timing chart diagram which shows an example of the photon count operation of the photodetector which concerns on this embodiment. 図１３３の（１）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (1) of FIG. 図１３３の（２）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical cross-sectional view explaining the state of the photodetector at the timing of (2) of FIG. 図１３３の（３）のタイミングにおける光検出装置の状態を説明する縦断面図である。It is a vertical sectional view explaining the state of the photodetector device at the timing of (3) of FIG. フォトンカウント動作を実行する画素アレイに本実施形態に係る光検出装置を適用した場合の機能構成を示すブロック図である。It is a block diagram which shows the functional structure when the photodetector which concerns on this embodiment is applied to the pixel array which executes a photon count operation. 本開示の第７の実施形態に係る光検出装置の構造を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector which concerns on 7th Embodiment of this disclosure. 光検出装置から出力される電流の時間応答のばらつきを説明するグラフ図である。It is a graph which explains the variation of the time response of the current output from a photodetector. 図１３７に示す時間応答のばらつきに対する線形性のずれを示すグラフ図である。It is a graph which shows the deviation of the linearity with respect to the variation of the time response shown in FIG. 137. 同実施形態に係る光検出装置の画素アレイ構成を示す平面図である。It is a top view which shows the pixel array structure of the photodetector which concerns on this embodiment. 図１３９に示す画素アレイにおける通常画素の出力と、参照画素の出力との関係を示すグラフ図である。It is a graph which shows the relationship between the output of a normal pixel and the output of a reference pixel in the pixel array shown in FIG. 139. 通常画素と、参照画素との平面配置の第１のバリエーションを説明する模式的な平面図である。It is a schematic plan view explaining the first variation of the plane arrangement of a normal pixel and a reference pixel. 図１４１のＡ－ＡＡ切断面における断面構成を示す縦断面図である。It is a vertical cross-sectional view which shows the cross-sectional structure in the AA cut surface of FIG. 141. 通常画素と、参照画素との平面配置の第２のバリエーションを説明する模式的な平面図である。It is a schematic plan view explaining the 2nd variation of the plane arrangement of a normal pixel and a reference pixel. 図１４３のＢ－ＢＢ切断面における断面構成を示す縦断面図である。It is a vertical cross-sectional view which shows the cross-sectional structure in the B-BB cut plane of FIG. 143. 通常画素と、参照画素との平面配置の第３のバリエーションを説明する模式的な平面図である。It is a schematic plan view explaining the third variation of the plane arrangement of a normal pixel and a reference pixel. 図１４５のＣ－ＣＣ切断面における断面構成を示す縦断面図である。It is a vertical cross-sectional view which shows the cross-sectional structure in the C-CC cut plane of FIG. 145. 通常画素と、参照画素との平面配置の第４のバリエーションを説明する模式的な平面図である。It is a schematic plan view explaining the 4th variation of the plane arrangement of a normal pixel and a reference pixel. 通常画素と、参照画素との断面構成の第５のバリエーションを示す縦断面図である。It is a vertical cross-sectional view which shows the 5th variation of the cross-sectional structure of a normal pixel and a reference pixel. 参照画素の開口面積と、順電流の立ち上がりの遅延時間との対応関係を示すグラフ図である。It is a graph which shows the correspondence relationship between the aperture area of a reference pixel, and the delay time of the rise of a forward current. 同実施形態に係る光検出装置を画素アレイとした場合の第１の回路構成を示すブロック図である。It is a block diagram which shows the 1st circuit configuration when the photodetector which concerns on this embodiment is a pixel array. 同実施形態に係る光検出装置を画素アレイとした場合の第２の回路構成を示すブロック図である。It is a block diagram which shows the 2nd circuit structure when the photodetector which concerns on this embodiment is a pixel array. 同実施形態に係る光検出装置を画素アレイとした場合の第３の回路構成を示すブロック図である。It is a block diagram which shows the 3rd circuit configuration when the photodetector which concerns on this embodiment is a pixel array. 同実施形態に係る光検出装置を画素アレイとした場合の第４の回路構成を示すブロック図である。It is a block diagram which shows the 4th circuit structure when the photodetector which concerns on this embodiment is a pixel array. 光検出装置の積層構造の一例を示す模式的な斜視図である。It is a schematic perspective view which shows an example of the laminated structure of a photodetector. 光検出装置が適用される固体撮像素子の基板構成を示す斜視図である。It is a perspective view which shows the substrate structure of the solid-state image sensor to which a photodetector is applied. 光検出装置の受光チップにおける平面構成を示す平面図である。It is a top view which shows the plane structure of the light receiving chip of a photodetector. 光検出装置のロジックチップにおける平面構成を示す平面図である。It is a top view which shows the plane structure in the logic chip of a photodetector. 光検出装置の回路構成を示すブロック図である。It is a block diagram which shows the circuit structure of the photodetector. 光検出装置が適用される固体撮像装置の構成を示すブロック図である。It is a block diagram which shows the structure of the solid-state image sensor to which a photodetector is applied. 光検出装置が適用される固体撮像装置の有効画素における断面構成例を示す縦断面図である。It is a vertical sectional view which shows the example of the sectional composition in the effective pixel of the solid-state image sensor to which a light detection apparatus is applied. 光検出装置が適用される固体撮像装置の遮蔽画素における断面構成例を示す縦断面図である。It is a vertical cross-sectional view which shows the example of the cross-sectional structure in the shielding pixel of the solid-state image sensor to which a photodetector is applied. 光検出装置を用いたセンサチップを利用した電子機器である距離画像センサの構成例を示すブロック図である。It is a block diagram which shows the structural example of the distance image sensor which is an electronic device using the sensor chip which used the photodetector. 光検出装置を用いて測距情報を出力する測距モジュールの構成例を示すブロック図である。It is a block diagram which shows the configuration example of the distance measurement module which outputs the distance measurement information by using an optical detection device. 信号キャリアとして電子を用いる場合の光検出装置の構成を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector when the electron is used as a signal carrier. 信号キャリアとして正孔を用いる場合の光検出装置の構成を示す縦断面図である。It is a vertical cross-sectional view which shows the structure of the photodetector when a hole is used as a signal carrier.
　以下、本開示における実施形態について、図面を参照して詳細に説明する。以下で説明する実施形態は本開示の一具体例であって、本開示にかかる技術が以下の態様に限定されるわけではない。また、本開示の各構成要素の配置、寸法、及び寸法比等についても、各図に示す様態に限定されるわけではない。 Hereinafter, embodiments in the present disclosure will be described in detail with reference to the drawings. The embodiments described below are specific examples of the present disclosure, and the technique according to the present disclosure is not limited to the following aspects. Further, the arrangement, dimensions, dimensional ratio, etc. of each component of the present disclosure are not limited to the modes shown in the respective figures.
　なお、説明は以下の順序で行う。
　０．光検出装置の原理
　１．第１の実施形態
　２．第２の実施形態
　３．第３の実施形態
　４．第４の実施形態
　５．第５の実施形態
　６．第６の実施形態
　７．第７の実施形態
　８．適用例
　９．付記 The explanation will be given in the following order.
0. Principle of photodetector 1. First Embodiment 2. Second embodiment 3. Third embodiment 4. Fourth embodiment 5. Fifth embodiment 6. Sixth Embodiment 7. Seventh Embodiment 8. Application example 9. Addendum
　＜０．光検出装置の原理＞
　まず、図１～図４を参照して、本開示の一実施形態に係る光検出装置の光検出の原理について説明する。図１は、本実施形態に係る光検出装置１０の基本構成を模式的に示す説明図である。図２は、光検出装置１０の電流－電圧特性を示す模式的なグラフ図である。図３は、光検出装置１０に印加されるバイアス電圧の極性変化を示すグラフ図であり、図４は、バイアス電圧の極性変化に応じて光検出装置１０から流れる電流の遅延を示すグラフ図である。 <0. Principle of photodetector>
First, the principle of light detection of the photodetector according to the embodiment of the present disclosure will be described with reference to FIGS. 1 to 4. FIG. 1 is an explanatory diagram schematically showing a basic configuration of a photodetector 10 according to the present embodiment. FIG. 2 is a schematic graph showing the current-voltage characteristics of the photodetector 10. FIG. 3 is a graph showing a change in the polarity of the bias voltage applied to the photodetector 10, and FIG. 4 is a graph showing the delay of the current flowing from the photodetector 10 in response to the change in the polarity of the bias voltage. is there.
　なお、本明細書において、縦方向又は上下方向とは、基板又は層の厚み方向を示すものとする。また、横方向又は左右方向とは、基板又は層の面内の一方向（例えば、断面図における基板又は層の切断方向）を示すものとする。 In the present specification, the vertical direction or the vertical direction means the thickness direction of the substrate or the layer. Further, the lateral direction or the left-right direction means one direction in the plane of the substrate or layer (for example, the cutting direction of the substrate or layer in the cross-sectional view).
　図１に示すように、本実施形態に係る光検出装置１０は、第１領域１１と、第２領域１２と、第１領域１１及び第２領域１２の間に設けられた第３領域１３とを備える。 As shown in FIG. 1, the photodetector 10 according to the present embodiment includes a first region 11, a second region 12, and a third region 13 provided between the first region 11 and the second region 12. To be equipped with.
　第１領域１１は、例えば、グランド等に電気的に接続された第１導電型（例えば、Ｎ型）の半導体領域である。第２領域１２は、印加電圧を制御可能な電極に電気的に接続された第２導電型（例えば、Ｐ型）の半導体領域である。第３領域１３は、第１領域１１及び第２領域１２の間に設けられ、入射光を吸収する第３導電型（例えば、Ｉ型）の半導体領域である。 The first region 11 is, for example, a first conductive type (for example, N type) semiconductor region electrically connected to a ground or the like. The second region 12 is a second conductive type (for example, P type) semiconductor region electrically connected to an electrode whose applied voltage can be controlled. The third region 13 is a third conductive type (for example, type I) semiconductor region provided between the first region 11 and the second region 12 and absorbs incident light.
　すなわち、光検出装置１０は、いわゆるＰＩＮダイオードであり、図２に示すように、印加されるバイアスの極性によって電圧－電流特性が大きく変化する。具体的には、第２領域１２に負電圧が印加された状態では逆バイアスとなるため、印加されるバイアス電圧に依らず、第１領域１１及び第２領域１２の間には電流はほとんど流れない。一方、第２領域１２に正電圧が印加された順バイアスの状態では順バイアスとなるため、印加されるバイアス電圧の上昇に伴って、第１領域１１及び第２領域１２の間に急激に電流が流れるようになる。 That is, the photodetector 10 is a so-called PIN diode, and as shown in FIG. 2, the voltage-current characteristic greatly changes depending on the polarity of the applied bias. Specifically, since a negative voltage is applied to the second region 12, a reverse bias is applied, so that almost no current flows between the first region 11 and the second region 12 regardless of the applied bias voltage. Absent. On the other hand, in the forward bias state in which the positive voltage is applied to the second region 12, the forward bias occurs. Therefore, as the applied bias voltage increases, the current suddenly flows between the first region 11 and the second region 12. Will flow.
　ここで、図３及び図４に示すように、光検出装置１０に印加するバイアスの極性を逆バイアスから順バイアスに変化させた場合、光検出装置１０から流れる電流が電流ＩＲ（バイアス電圧ＶＲに対応）から電流ＩＦ（バイアス電圧ＶＦに対応）に増加するまでには、時間ｔの遅延が生じる。このとき、電流ＩＲから電流ＩＦへの変化の遅延時間ｔは、光検出装置１０の第３領域１３にて吸収される光強度に応じて変化する。したがって、印加されるバイアスの極性を変化させた際の電流増加の遅延時間を測定することで、光検出装置１０は、入射した光の強度を見積もることができる。このような光検出装置１０は、例えば、ＤＰＤ（Ｄｙｎａｍｉｃ　ＰｈｏｔｏＤｉｏｄｅ）センサとも称される。 Here, as shown in FIGS. 3 and 4, when the polarity of the bias applied to the photodetector 10 from the reverse bias is changed to a forward bias, current flows from the photodetector 10 current I R (bias voltage V to until an increase in current from the corresponding R) I F (corresponding to the bias voltage V F), resulting a delay of time t. At this time, the delay time t changes to current I F from the current I R changes according to the intensity of the light absorbed by the third region 13 of the photodetector 10. Therefore, the photodetector 10 can estimate the intensity of the incident light by measuring the delay time of the current increase when the polarity of the applied bias is changed. Such a photodetector 10 is also referred to as, for example, a DPD (Dynamic Photodiode) sensor.
　続いて、図５Ａ～図５Ｃを参照して、光検出装置１０に入射する光の強度と、バイアス電圧の変化に対する電流の増加の遅延時間との対応関係についてより具体的に説明する。図５Ａ～図５Ｃは、光検出装置１０に入射する光と、バイアス電圧の変化に対する電流増加の遅延時間との関係の一例を示す模式的なグラフ図である。 Subsequently, with reference to FIGS. 5A to 5C, the correspondence between the intensity of the light incident on the photodetector 10 and the delay time of the increase in the current with respect to the change in the bias voltage will be described more specifically. 5A to 5C are schematic graphs showing an example of the relationship between the light incident on the photodetector 10 and the delay time of the current increase with respect to the change in the bias voltage.
　図５Ａに示すように、光が入射していない場合、光検出装置１０では、バイアス電圧の極性変化に対する電流増加の遅延時間がｔ１であるとする。このような光検出装置１０では、光が入射することで、図５Ｂに示すように、バイアス電圧の極性変化に対する電流増加の遅延時間がｔ１よりも短いｔ２となる。さらに、光検出装置１０では、図５Ｂの状態よりも強い光が入射することで、図５Ｃに示すように、バイアス電圧の極性変化に対する電流増加の遅延時間がｔ３よりもさらに短いｔ３となる。したがって、このような光検出装置１０によれば、バイアス電圧の極性変化から電流が増加するまでの時間を測定することで、入射光量を算出することができる。 As shown in FIG. 5A, when light is not incident, the photodetector 10, the delay time of the current increase for a polarity change of the bias voltage is assumed to be t 1. In such a photodetector 10, when light is incident, as shown in FIG. 5B, the delay time of the current increase with respect to the change in the polarity of the bias voltage becomes t 2 , which is shorter than t 1 . Further, the photodetector 10, that the intense light than in the state of FIG. 5B is incident, as shown in FIG. 5C, the delay time of the current increase for a polarity change of the bias voltage and the shorter t 3 than t 3 Become. Therefore, according to such a photodetector 10, the amount of incident light can be calculated by measuring the time from the change in the polarity of the bias voltage to the increase in the current.
　さらに、図６～図９Ｄを参照して、光検出装置１０において、入射光量に応じて電流増加までの遅延時間が変化する原理についてより詳細に説明する。図６は、光検出装置１０のより具体的な構成を示す縦断面図である。図７は、バイアス電圧の変化に対する電流の変化を示すグラフ図である。図８Ａ～図８Ｄは、図７の（１）～（４）の各々のタイミングにおける光検出装置１０の電子及び正孔の動きを示す縦断面図である。図９Ａ～図９Ｄは、図７の（１）～（４）の各々のタイミングにおける光検出装置１０のＡ－ＡＡ切断面でのエネルギーバンド構造を示すグラフ図である。 Further, with reference to FIGS. 6 to 9D, the principle that the delay time until the current increase changes according to the amount of incident light in the photodetector 10 will be described in more detail. FIG. 6 is a vertical cross-sectional view showing a more specific configuration of the photodetector 10. FIG. 7 is a graph showing a change in current with respect to a change in bias voltage. 8A to 8D are vertical cross-sectional views showing the movement of electrons and holes of the photodetector 10 at each timing of FIGS. 7 (1) to 7 (4). 9A to 9D are graphs showing the energy band structure at the AAA cut surface of the photodetector 10 at each timing of FIGS. 7 (1) to 9D.
　図６に示すように、光検出装置１０は、例えば、第１領域１１と、第２領域１２と、第３領域１３と、第１電極２１と、第１面絶縁層１６と、画素分離層１５と、第２電極２２と、制御ゲート２５と、ゲート絶縁膜２６とを備える。 As shown in FIG. 6, the photodetector 10 includes, for example, a first region 11, a second region 12, a third region 13, a first electrode 21, a first surface insulating layer 16, and a pixel separation layer. A 15, second electrode 22, a control gate 25, and a gate insulating film 26 are provided.
　第１領域１１は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域１２は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域１３は、シリコン（Ｓｉ）などの半導体基板の第１領域１１と第２領域１２との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 11 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 12 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The third region 13 is a third conductive type region (for example, layer i) provided between the first region 11 and the second region 12 of a semiconductor substrate such as silicon (Si).
　第１電極２１は、半導体基板の第１面の上に第１面絶縁層１６を介して設けられ、第１面絶縁層１６を貫通するビア等を介して第１領域１１と電気的に接続する。第１電極２１は、例えば、カソード電極として機能する。 The first electrode 21 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 16, and is electrically connected to the first region 11 via a via or the like penetrating the first surface insulating layer 16. To do. The first electrode 21 functions as, for example, a cathode electrode.
　画素分離層１５は、絶縁体にて半導体基板を厚み方向に貫通して設けられる。画素分離層１５は、例えば、半導体基板の面内方向に複数設けられた画素の各々を互いに電気的に離隔するために設けられる。 The pixel separation layer 15 is provided with an insulator penetrating the semiconductor substrate in the thickness direction. The pixel separation layer 15 is provided, for example, to electrically separate each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other.
　第２電極２２は、半導体基板の第２面の上に設けられ、第２領域１２と電気的に接続する。第２電極２２は、例えば、アノード電極として機能する。 The second electrode 22 is provided on the second surface of the semiconductor substrate and is electrically connected to the second region 12. The second electrode 22 functions as, for example, an anode electrode.
　制御ゲート２５は、半導体基板の第２面の上にゲート絶縁膜２６を介して設けられるゲート電極である。制御ゲート２５は、電圧印加によって、第３領域１３における後述するポテンシャル障壁ＰＢの高さを制御するために設けられる。 The control gate 25 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 26. The control gate 25 is provided to control the height of the potential barrier PB described later in the third region 13 by applying a voltage.
　第１電極２１、第２電極２２、及び制御ゲート２５は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。第１面絶縁層１６、画素分離層１５、及びゲート絶縁膜２６は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 21, the second electrode 22, and the control gate 25 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalu (Ta), and polysilicon (Ta). It may be provided with poly—Si) or other conductive material. The first surface insulating layer 16, the pixel separating layer 15, and the gate insulating film 26 are insulators such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. It may be provided at.
　ここで、図７に示すように、第１電極２１に印加される電圧をＶｃ、第２電極２２に印加される電圧をＶａ、制御ゲート２５に印加される電圧をＶｇとする。このような場合、光検出装置１０は、例えば、第１電極２１の電圧Ｖｃを０Ｖに制御し、第２電極２２の電圧Ｖａ、及び制御ゲート２５の電圧Ｖｇを－１Ｖに制御することで、逆バイアスモードに制御され得る。また、光検出装置１０は、例えば、第１電極２１の電圧Ｖｃを０Ｖに制御し、第２電極２２の電圧Ｖａ、及び制御ゲート２５の電圧Ｖｇを＋１Ｖに制御することで、順バイアスモードに制御され得る。 Here, as shown in FIG. 7, the voltage applied to the first electrode 21 is Vc, the voltage applied to the second electrode 22 is Va, and the voltage applied to the control gate 25 is Vg. In such a case, the photodetector 10 controls, for example, the voltage Vc of the first electrode 21 to 0V, and controls the voltage Va of the second electrode 22 and the voltage Vg of the control gate 25 to -1V. It can be controlled to reverse bias mode. Further, the optical detection device 10 is set to the forward bias mode by, for example, controlling the voltage Vc of the first electrode 21 to 0V and controlling the voltage Va of the second electrode 22 and the voltage Vg of the control gate 25 to + 1V. Can be controlled.
　ここで、逆バイアスモードの状態（１）では、図８Ａに示すように、第３領域１３内の電子ｅは、第１領域１１に排出され、第３領域１３内の正孔ｈは、第２領域１２に排出される。したがって、このときの光検出装置１０のエネルギーバンド構造は、図９Ａに示すように、第２領域１２側が高く、第１領域１１側が低い構造となるため、第３領域１３は空乏状態となる。 Here, in the reverse bias mode state (1), as shown in FIG. 8A, the electrons e in the third region 13 are discharged to the first region 11, and the holes h in the third region 13 are the third. It is discharged to 2 regions 12. Therefore, as shown in FIG. 9A, the energy band structure of the photodetector 10 at this time has a structure in which the second region 12 side is high and the first region 11 side is low, so that the third region 13 is in a depleted state.
　次に、逆バイアスモードから順バイアスモードに電圧の極性が変更された状態（２）では、図８Ｂに示すように、第１領域１１及び第２領域１２に隣接する領域にポテンシャル障壁ＰＢが発生する。すなわち、このときの光検出装置１０のエネルギーバンド構造は、図９Ｂに示すように、第１領域１１及び第２領域１２の間に凹又は凸となるポテンシャル障壁ＰＢを有する構造となるため、第３領域１３における電子ｅ及び正孔ｈの流れが妨げられ、光検出装置１０にはほとんど電流が流れない。 Next, in the state (2) in which the polarity of the voltage is changed from the reverse bias mode to the forward bias mode, a potential barrier PB is generated in a region adjacent to the first region 11 and the second region 12 as shown in FIG. 8B. To do. That is, as shown in FIG. 9B, the energy band structure of the photodetector 10 at this time has a structure having a concave or convex potential barrier PB between the first region 11 and the second region 12. The flow of electrons e and holes h in the three regions 13 is obstructed, and almost no current flows through the photodetector 10.
　続いて、順バイアスモードの光検出装置１０に光が照射された状態（３）では、図８Ｃに示すように、入射光を光電変換した電子ｅ及び正孔ｈが空乏状態の第３領域１３に発生する。このとき、光検出装置１０のエネルギーバンド構造では、図９Ｃに示すように、入射光を光電変換した電子ｅ及び正孔ｈによってポテンシャル障壁ＰＢの高さが低下する。これにより、徐々に、第１領域１１から電子ｅが流れ出し、又は第２領域１２から正孔ｈが流れ出すため、流れ出した電子ｅ及び正孔ｈによって、ポテンシャル障壁ＰＢの高さがさらに低下する。 Subsequently, in the state (3) in which the photodetector 10 in the forward bias mode is irradiated with light, as shown in FIG. 8C, the third region 13 in which the electrons e and holes h obtained by photoelectrically converting the incident light are depleted. Occurs in. At this time, in the energy band structure of the light detection device 10, as shown in FIG. 9C, the height of the potential barrier PB is lowered by the electrons e and holes h that are photoelectrically converted from the incident light. As a result, the electrons e gradually flow out from the first region 11 or the holes h flow out from the second region 12, so that the height of the potential barrier PB is further lowered by the flowed out electrons e and holes h.
　その結果、順バイアスモードの状態（４）では、図８Ｄに示すように、第１領域１１及び第２領域１２に隣接する領域に発生したポテンシャル障壁ＰＢが消失するため、光検出装置１０では順方向の電流が流れるようになる。すなわち、このときの光検出装置１０のエネルギーバンド構造は、図９Ｄに示すように、第１領域１１及び第２領域１２の間に存在した凹又は凸のポテンシャル障壁ＰＢが消失した略平坦な構造となる。 As a result, in the forward bias mode state (4), as shown in FIG. 8D, the potential barrier PB generated in the regions adjacent to the first region 11 and the second region 12 disappears, so that the photodetector 10 sequentially A current in the direction will flow. That is, as shown in FIG. 9D, the energy band structure of the photodetector 10 at this time is a substantially flat structure in which the concave or convex potential barrier PB existing between the first region 11 and the second region 12 disappears. It becomes.
　したがって、光検出装置１０では、印加されるバイアスの極性が逆バイアスから順バイアスに変化した際のポテンシャル障壁ＰＢの消失速度が光の入射量によって異なることになる。よって、光検出装置１０は、順方向の電流が流れ始めるまでの時間にて、ポテンシャル障壁ＰＢの消失までの時間を計測することで、光の入射量を計測することができる。 Therefore, in the light detection device 10, the disappearance rate of the potential barrier PB when the polarity of the applied bias changes from the reverse bias to the forward bias differs depending on the incident amount of light. Therefore, the photodetector 10 can measure the incident amount of light by measuring the time until the potential barrier PB disappears in the time until the forward current starts to flow.
　以下では、上記で原理を説明した光検出装置１０のより具体的な構造について、第１～第７の実施形態に分けてそれぞれ説明する。なお、以下において画素とは、本開示における「光電変換部」の一具体例に対応する。 In the following, a more specific structure of the photodetector 10 whose principle has been described above will be described separately for the first to seventh embodiments. In the following, the pixel corresponds to a specific example of the "photoelectric conversion unit" in the present disclosure.
　＜１．第１の実施形態＞
　（基本構造）
　まず、図１０及び図１１を参照して、本開示の第１の実施形態に係る光検出装置の基本構造について説明する。図１０は、本実施形態に係る光検出装置３００の基本構造を示す縦断面図であり、図１１は、本実施形態に係る光検出装置３００の基本構造を示す第１面側からの平面図である。 <1. First Embodiment>
(Basic structure)
First, the basic structure of the photodetector according to the first embodiment of the present disclosure will be described with reference to FIGS. 10 and 11. FIG. 10 is a vertical sectional view showing the basic structure of the photodetector 300 according to the present embodiment, and FIG. 11 is a plan view from the first surface side showing the basic structure of the photodetector 300 according to the present embodiment. Is.
　図１１に示すように、光検出装置３００は、例えば、第１領域３１０と、第２領域３２０と、第３領域３３０と、第１電極３１１と、上部第１電極３１２と、画素分離層３５１と、上部画素分離層３５２と、第１面絶縁層３５３と、第２電極３２１と、制御ゲート３６１と、ゲート絶縁膜３６２とを備える。 As shown in FIG. 11, the photodetector 300 includes, for example, a first region 310, a second region 320, a third region 330, a first electrode 311 and an upper first electrode 312, and a pixel separation layer 351. The upper pixel separation layer 352, the first surface insulating layer 353, the second electrode 321 and the control gate 361, and the gate insulating film 362 are provided.
　第１領域３１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第１領域３１０は、半導体基板の第１面と、半導体基板の第１面から半導体基板の厚み方向に延在する上部第１電極３１２（詳細は後述する）の側面に設けられた上部画素分離層３５２とに沿った領域に設けられる。 The first region 310 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The first region 310 is an upper pixel separation provided on the first surface of the semiconductor substrate and the side surface of the upper first electrode 312 (details will be described later) extending from the first surface of the semiconductor substrate in the thickness direction of the semiconductor substrate. It is provided in a region along the layer 352.
　第２領域３２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。 The second region 320 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si).
　第３領域３３０は、シリコン（Ｓｉ）などの半導体基板の第１領域３１０と第２領域３２０との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The third region 330 is a third conductive type region (for example, layer i) provided between the first region 310 and the second region 320 of a semiconductor substrate such as silicon (Si).
　第１電極３１１は、各画素の境界にて半導体基板の第２面から半導体基板の厚み方向に延在して設けられ、第１電極３１１よりも幅が小さい上部第１電極３１２と底面にて当接する。上部第１電極３１２は、第１電極３１１よりも幅が小さく、第１電極３１１の底面から半導体基板の第２面まで半導体基板の厚み方向に延在して設けられる。 The first electrode 311 is provided at the boundary of each pixel extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, and is provided at the upper first electrode 312 and the bottom surface, which are smaller in width than the first electrode 311. Contact. The upper first electrode 312 has a width smaller than that of the first electrode 311 and is provided extending from the bottom surface of the first electrode 311 to the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate.
　ここで、第１電極３１１の幅は、上部第１電極３１２の幅よりも大きいため、第１電極３１１の上部第１電極３１２と当接する底面の一部は、上部第１電極３１２にて覆われなくなる。したがって、第１電極３１１は、第１電極３１１の底面の一部にて、上部第１電極３１２の側面に沿って設けられた第１領域３１０と電気的に接続することができる。第１電極３１１及び上部第１電極３１２は、例えば、カソード電極として機能し、半導体基板の第２面側から配線層に電気的に接続される。 Here, since the width of the first electrode 311 is larger than the width of the upper first electrode 312, a part of the bottom surface of the first electrode 311 in contact with the upper first electrode 312 is covered with the upper first electrode 312. I won't be able to. Therefore, the first electrode 311 can be electrically connected to the first region 310 provided along the side surface of the upper first electrode 312 at a part of the bottom surface of the first electrode 311. The first electrode 311 and the upper first electrode 312 function as, for example, a cathode electrode, and are electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
　第１電極３１１及び上部第１電極３１２は、例えば、半導体基板を厚み方向に第２面から第１面まで貫通する第１の開口と、第１の開口よりも開口幅が大きく、半導体基板を厚み方向に半ばまで掘り込む第２の開口とを導電性材料で埋め込むことで形成され得る。すなわち、上部第１電極３１２は、第１の開口に導電材料を埋め込むことで形成され得、第１電極３１１は、第２の開口に導電材料を埋め込むことで形成され得る。 The first electrode 311 and the upper first electrode 312 have, for example, a first opening penetrating the semiconductor substrate from the second surface to the first surface in the thickness direction, and an opening width larger than that of the first opening, so that the semiconductor substrate can be formed. It can be formed by embedding a second opening that is dug halfway in the thickness direction with a conductive material. That is, the upper first electrode 312 may be formed by embedding a conductive material in the first opening, and the first electrode 311 may be formed by embedding a conductive material in the second opening.
　画素分離層３５１は、第１電極３１１の側面に設けられ、上部画素分離層３５２は、上部第１電極３１２の側面に設けられる。これにより、画素分離層３５１及び上部画素分離層３５２は、第１電極３１１及び上部第１電極３１２のうち、第１電極３１１及び上部第１電極３１２の段差の上面を第１領域３１０に対して露出させることができる。したがって、画素分離層３５１及び上部画素分離層３５２は、半導体基板の面内方向に隣接して設けられた光検出装置３００の各々を互いに電気的に離隔しつつ、第１電極３１１を第１領域３１０に電気的に接続させることができる。 The pixel separation layer 351 is provided on the side surface of the first electrode 311 and the upper pixel separation layer 352 is provided on the side surface of the upper first electrode 312. As a result, the pixel separation layer 351 and the upper pixel separation layer 352 display the upper surface of the step of the first electrode 311 and the upper first electrode 312 with respect to the first region 310 among the first electrode 311 and the upper first electrode 312. Can be exposed. Therefore, the pixel separation layer 351 and the upper pixel separation layer 352 electrically separate the photodetectors 300 provided adjacent to each other in the in-plane direction of the semiconductor substrate from each other, and set the first electrode 311 in the first region. It can be electrically connected to 310.
　第１面絶縁層３５３は、半導体基板の第１面の上に設けられる。第１面絶縁層３５３は、例えば、第１領域３１０を含む半導体基板を外界から保護することができる。 The first surface insulating layer 353 is provided on the first surface of the semiconductor substrate. The first surface insulating layer 353 can protect the semiconductor substrate including the first region 310 from the outside world, for example.
　したがって、図１１に示すように、光検出装置３００の半導体基板の第１面側では、第１電極３１１、上部第１電極３１２、及びこれらの電極と電気的に接続する配線が形成されず、第１面絶縁層３５３が全面に広がって形成されるようになる。よって、光検出装置３００は、光入射面である第１面における開口率を増加させることができる。 Therefore, as shown in FIG. 11, on the first surface side of the semiconductor substrate of the photodetector 300, the first electrode 311 and the upper first electrode 312, and the wiring electrically connected to these electrodes are not formed. The first surface insulating layer 353 is formed so as to spread over the entire surface. Therefore, the photodetector 300 can increase the aperture ratio on the first surface, which is the light incident surface.
　第２電極３２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域３２０と電気的に接続する。第２電極３２１は、例えば、アノード電極として機能し、半導体基板の第２面側から配線層に電気的に接続される。 The second electrode 321 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 320. The second electrode 321 functions as, for example, an anode electrode and is electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
　制御ゲート３６１は、半導体基板の第２面の上にゲート絶縁膜３６２を介して設けられるゲート電極である。制御ゲート３６１は、電圧印加によって、第３領域３３０におけるポテンシャル障壁を制御するために設けられる。 The control gate 361 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 362. The control gate 361 is provided to control the potential barrier in the third region 330 by applying a voltage.
　第１電極３１１、上部第１電極３１２、第２電極３２１、及び制御ゲート３６１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。画素分離層３５１、上部画素分離層３５２、第１面絶縁層３５３、及びゲート絶縁膜３６２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 311, the upper first electrode 312, the second electrode 321 and the control gate 361 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), tantalum (Ta) or the like. It may be provided by the metal, polysilicon (poly-Si), or other conductive material. The pixel separation layer 351, the upper pixel separation layer 352, the first surface insulating layer 353, and the gate insulating film 362 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or so-called low-. It may be provided with an insulator such as k material.
　本実施形態に係る光検出装置３００は、裏面（すなわち、第１面）照射型のＣＭＯＳ（Ｃｏｍｐｌｅｍｅｎｔａｒｙ　ＭＯＳ）イメージセンサとして設けられることで、光入射面である裏面側の開口率を増加させることができる。具体的には、光検出装置３００は、半導体基板の第２面から半導体基板の厚み方向に延在する第１電極３１１を用いることによって、第１領域３１０に対して半導体基板の第２面側からカソード電極を電気的に接続することができる。したがって、光検出装置３００は、第１領域３１０及び第２領域３２０に電気的に接続する各種電極及び配線を半導体基板の光入射面の反対側の表面（すなわち、第２面）に設けることで、光入射面である裏面（すなわち、第１面）の開口率を増加させることができる。 The photodetector 300 according to the present embodiment is provided as a back surface (that is, the first surface) irradiation type CMOS (Complementary MOS) image sensor, so that the aperture ratio on the back surface side, which is the light incident surface, can be increased. it can. Specifically, the light detection device 300 uses the first electrode 311 extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, so that the second surface side of the semiconductor substrate is relative to the first region 310. The cathode electrode can be electrically connected from. Therefore, the light detection device 300 is provided with various electrodes and wirings electrically connected to the first region 310 and the second region 320 on the surface (that is, the second surface) opposite to the light incident surface of the semiconductor substrate. , The aperture ratio of the back surface (that is, the first surface) which is the light incident surface can be increased.
　また、本実施形態に係る光検出装置３００は、半導体基板の厚み方向に第１領域３１０及び第２領域３２０が配置されるため、占有面積をより小さくすることができる。これによれば、光検出装置３００は、より効率的に画素を微細化することが可能である。さらに、本実施形態に係る光検出装置３００は、半導体基板の厚み方向に延在する画素分離層３５１及び上部画素分離層３５２によって、画素間のクロストークを抑制することができるため、ノイズをより低減することが可能である。 Further, in the photodetector 300 according to the present embodiment, since the first region 310 and the second region 320 are arranged in the thickness direction of the semiconductor substrate, the occupied area can be made smaller. According to this, the photodetector 300 can miniaturize the pixels more efficiently. Further, the photodetector 300 according to the present embodiment can suppress crosstalk between pixels by the pixel separation layer 351 and the upper pixel separation layer 352 extending in the thickness direction of the semiconductor substrate, so that noise can be further reduced. It can be reduced.
　（バリエーション）
　続いて、図１２Ａ～図２７を参照して、本実施形態に係る光検出装置３００の構造のバリエーションについて説明する。 (variation)
Subsequently, with reference to FIGS. 12A to 27, variations in the structure of the photodetector 300 according to the present embodiment will be described.
　（第１のバリエーション）
　図１２Ａは、第１のバリエーションに係る光検出装置３００の構造を示す縦断面図である。図１２Ｂは、第１のバリエーションに係る光検出装置３００の構造を示す第２面側から見た平面図である。 (First variation)
FIG. 12A is a vertical cross-sectional view showing the structure of the photodetector 300 according to the first variation. FIG. 12B is a plan view of the photodetector 300 according to the first variation as viewed from the second surface side.
　図１２Ａ及び図１２Ｂに示すように、第１電極３１１は、画素に相当する矩形形状の領域の全周を囲むように設けられ、画素分離層３５１は、第１電極３１１の矩形形状の内側に沿って設けられる。第２領域３２０は、例えば、第１電極３１１及び画素分離層３５１にて画定された領域の略中央に島状に設けられてもよい。また、制御ゲート３６１及びゲート絶縁膜３６２は、例えば、半導体基板の面内方向において、第２領域３２０の周囲を囲むように設けられてもよい。 As shown in FIGS. 12A and 12B, the first electrode 311 is provided so as to surround the entire circumference of the rectangular region corresponding to the pixel, and the pixel separation layer 351 is inside the rectangular shape of the first electrode 311. It is provided along. The second region 320 may be provided, for example, in an island shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351. Further, the control gate 361 and the gate insulating film 362 may be provided, for example, so as to surround the second region 320 in the in-plane direction of the semiconductor substrate.
　第１のバリエーションによれば、光検出装置３００Ａは、半導体基板の厚み方向に第１領域３１０及び第２領域３２０を配置することで、占有面積をより小さくすることができる。また、光検出装置３００Ａは、第１電極３１１の矩形形状の内側に画素分離層３５１を設けることで、画素間のクロストークを抑制することができる。 According to the first variation, the photodetector 300A can make the occupied area smaller by arranging the first region 310 and the second region 320 in the thickness direction of the semiconductor substrate. Further, the photodetector 300A can suppress crosstalk between pixels by providing the pixel separation layer 351 inside the rectangular shape of the first electrode 311.
　（第２のバリエーション）
　図１３は、第２のバリエーションに係る光検出装置３００Ｂの構造を示す縦断面図である。 (Second variation)
FIG. 13 is a vertical cross-sectional view showing the structure of the photodetector 300B according to the second variation.
　図１３に示すように、光検出装置３００Ｂでは、上部第１電極３１２及び上部画素分離層３５２が設けられなくともよい。このような場合、第１電極３１１は、半導体基板の第２面から半導体基板の厚み方向に延在して設けられ、底面にて第１領域３１０と電気的に接続することができる。このような構成であっても、光検出装置３００Ｂは、画素分離層３５１によって、隣接する画素間のクロストークを抑制することができる。 As shown in FIG. 13, the photodetector 300B does not have to be provided with the upper first electrode 312 and the upper pixel separation layer 352. In such a case, the first electrode 311 is provided extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate, and can be electrically connected to the first region 310 on the bottom surface. Even with such a configuration, the photodetector 300B can suppress crosstalk between adjacent pixels by the pixel separation layer 351.
　第２のバリエーションによれば、光検出装置３００Ｂは、上部第１電極３１２及び上部画素分離層３５２が設けられないため、製造工程の工程数をより低減することができる。また、光検出装置３００Ｂは、上部画素分離層３５２と第１領域３１０又は第３領域３３０との界面をなくすことで、暗電流の発生源となり得る界面をなくすことができるため、暗時ノイズを低減することができる。 According to the second variation, the photodetector 300B is not provided with the upper first electrode 312 and the upper pixel separation layer 352, so that the number of steps in the manufacturing process can be further reduced. Further, the photodetector 300B can eliminate the interface that can be a source of dark current by eliminating the interface between the upper pixel separation layer 352 and the first region 310 or the third region 330, so that dark noise can be eliminated. It can be reduced.
　（第３のバリエーション）
　図１４Ａは、第３のバリエーションに係る光検出装置３００Ｃの構造を示す縦断面図である。図１４Ｂは、第３のバリエーションに係る光検出装置３００Ｃの構造を示す第２面側から見た平面図である。 (Third variation)
FIG. 14A is a vertical cross-sectional view showing the structure of the photodetector 300C according to the third variation. FIG. 14B is a plan view of the photodetector 300C according to the third variation as viewed from the second surface side.
　図１４Ａに示すように、制御ゲート３６１Ｃは、縦型ゲート構造にて設けられてもよい。具体的には、制御ゲート３６１Ｃは、半導体基板の第２面側から半導体基板の厚み方向に延在するように設けられてもよい。また、半導体基板に埋め込まれた制御ゲート３６１Ｃの側面及び底面にはゲート絶縁膜３６２Ｃが設けられ、制御ゲート３６１Ｃの周囲には第２導電型（例えば、Ｐ型）の不純物領域３６３が設けられてもよい。このような場合、図１４Ｂに示すように、半導体基板の面内方向において、第２領域３２０の周囲を囲むように制御ゲート３６１Ｃが設けられ、さらに、制御ゲート３６１Ｃの周囲を囲むように第２導電型（例えば、Ｐ型）の不純物領域３６３が設けられることになる。 As shown in FIG. 14A, the control gate 361C may be provided in a vertical gate structure. Specifically, the control gate 361C may be provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate. Further, a gate insulating film 362C is provided on the side surface and the bottom surface of the control gate 361C embedded in the semiconductor substrate, and a second conductive type (for example, P type) impurity region 363 is provided around the control gate 361C. May be good. In such a case, as shown in FIG. 14B, the control gate 361C is provided so as to surround the periphery of the second region 320 in the in-plane direction of the semiconductor substrate, and further, the second control gate 361C is provided so as to surround the periphery of the control gate 361C. A conductive type (for example, P type) impurity region 363 will be provided.
　第３のバリエーションによれば、光検出装置３００Ｃは、第２領域３２０に隣接する領域に発生するポテンシャル障壁の制御性をより向上させることができるため、入射光の検出特性をより向上させることができる。 According to the third variation, the photodetector 300C can further improve the controllability of the potential barrier generated in the region adjacent to the second region 320, and thus can further improve the detection characteristics of the incident light. it can.
　（第４のバリエーション）
　図１５は、第４のバリエーションに係る光検出装置３００Ｄの構造を示す縦断面図である。 (Fourth variation)
FIG. 15 is a vertical cross-sectional view showing the structure of the photodetector 300D according to the fourth variation.
　図１５に示すように、制御ゲート３６１Ｄは、縦型ゲート構造にて設けられてもよい。また、不純物領域３６３には、電極３６４が電気的に接続されてもよい。電極３６４は、印加電圧Ｖｐｉｎによって不純物領域３６３の電位を制御することができる。 As shown in FIG. 15, the control gate 361D may be provided with a vertical gate structure. Further, the electrode 364 may be electrically connected to the impurity region 363. The electrode 364 can control the potential of the impurity region 363 by the applied voltage Vpin.
　第４のバリエーションによれば、光検出装置３００Ｄは、不純物領域３６３への印加電圧Ｖｐｉｎを負に制御することで、第２領域３２０のピニングの効果をより強くすることができる。したがって、光検出装置３００Ｄは、入射光の検出特性をより向上させることができる。 According to the fourth variation, the photodetector 300D can make the effect of pinning in the second region 320 stronger by controlling the voltage Vpin applied to the impurity region 363 to be negative. Therefore, the photodetector 300D can further improve the detection characteristics of the incident light.
　（第５のバリエーション）
　図１６は、第５のバリエーションに係る光検出装置３００Ｅの構造を示す縦断面図である。 (Fifth variation)
FIG. 16 is a vertical cross-sectional view showing the structure of the photodetector 300E according to the fifth variation.
　図１６に示すように、第２領域３２０、制御ゲート３６１Ｅ、ゲート絶縁膜３６２Ｅ、及び不純物領域３６３の半導体基板の厚み方向の形成深さは、画素ごとに異なっていてもよい。これによれば、光検出装置３００Ｅは、入射光を吸収する第３領域３３０の厚みを画素ごとに異ならせることができるため、第３領域３３０が吸収する光の波長帯域を画素ごとに変更することが可能になる。 As shown in FIG. 16, the formation depth of the semiconductor substrate in the second region 320, the control gate 361E, the gate insulating film 362E, and the impurity region 363 in the thickness direction may be different for each pixel. According to this, since the photodetector 300E can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
　第５のバリエーションによれば、光検出装置３００Ｅは、画素ごとに異なる波長帯域の光を検出することが可能となるため、より複雑なセンシングを行うことが可能である。 According to the fifth variation, the photodetector 300E can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
　（第６のバリエーション）
　図１７Ａは、第６のバリエーションに係る光検出装置３００Ｆの構造を示す縦断面図である。図１７Ｂは、第６のバリエーションに係る光検出装置３００Ｆの構造を示す第２面側から見た平面図である。 (Sixth variation)
FIG. 17A is a vertical cross-sectional view showing the structure of the photodetector 300F according to the sixth variation. FIG. 17B is a plan view of the photodetector 300F according to the sixth variation as viewed from the second surface side.
　図１７Ａに示すように、制御ゲート３６１Ｆは、縦型ゲート構造にて設けられ、第２領域３２０を貫通し、ゲート絶縁膜３６２Ｆを介して半導体基板に埋め込まれるように設けられてもよい。また、図１７Ｂに示すように、第２領域３２０は、半導体基板の面内方向において、第１電極３１１及び画素分離層３５１にて画定された領域の略中央に円形形状にて設けられ、制御ゲート３６１Ｆは、第２領域３２０の中心を貫通するように設けられてもよい。 As shown in FIG. 17A, the control gate 361F may be provided in a vertical gate structure, penetrates the second region 320, and is embedded in the semiconductor substrate via the gate insulating film 362F. Further, as shown in FIG. 17B, the second region 320 is provided in a circular shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351 in the in-plane direction of the semiconductor substrate, and is controlled. The gate 361F may be provided so as to penetrate the center of the second region 320.
　第６のバリエーションによれば、光検出装置３００Ｆは、第２領域３２０に隣接する領域に発生するポテンシャル障壁の制御性をより向上させることができるため、入射光の検出特性をより向上させることができる。 According to the sixth variation, the photodetector 300F can further improve the controllability of the potential barrier generated in the region adjacent to the second region 320, so that the detection characteristics of the incident light can be further improved. it can.
　（第７のバリエーション）
　図１８は、第７のバリエーションに係る光検出装置３００Ｇの構造を示す縦断面図である。 (7th variation)
FIG. 18 is a vertical cross-sectional view showing the structure of the photodetector 300G according to the seventh variation.
　図１８に示すように、制御ゲート３６１Ｇは、縦型ゲート構造にて設けられ、第２領域３２０を貫通し、ゲート絶縁膜３６２Ｇを介して半導体基板に埋め込まれるように設けられてもよい。また、第２領域３２０、制御ゲート３６１Ｇ、及びゲート絶縁膜３６２Ｇの半導体基板の厚み方向の形成深さは、画素ごとに異なっていてもよい。これによれば、光検出装置３００Ｇは、入射光を吸収する第３領域３３０の厚みを画素ごとに異ならせることができるため、第３領域３３０が吸収する光の波長帯域を画素ごとに変更することが可能になる。 As shown in FIG. 18, the control gate 361G may be provided in a vertical gate structure, penetrates the second region 320, and is embedded in the semiconductor substrate via the gate insulating film 362G. Further, the formation depth of the second region 320, the control gate 361G, and the gate insulating film 362G in the thickness direction of the semiconductor substrate may be different for each pixel. According to this, since the photodetector 300G can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
　第７のバリエーションによれば、光検出装置３００Ｇは、画素ごとに異なる波長帯域の光を検出することが可能となるため、より複雑なセンシングを行うことが可能である。 According to the seventh variation, the photodetector 300G can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
　（第８のバリエーション）
　図１９は、第８のバリエーションに係る光検出装置３００Ｈの構造を示す縦断面図である。 (8th variation)
FIG. 19 is a vertical cross-sectional view showing the structure of the photodetector 300H according to the eighth variation.
　図１９に示すように、第１領域３１０の半導体基板の厚み方向の形成深さは、画素ごとに異なっていてもよい。これによれば、光検出装置３００Ｈは、入射光を吸収する第３領域３３０の厚みを画素ごとに異ならせることができるため、第３領域３３０が吸収する光の波長帯域を画素ごとに変更することが可能になる。 As shown in FIG. 19, the formation depth of the semiconductor substrate in the first region 310 in the thickness direction may be different for each pixel. According to this, since the photodetector 300H can make the thickness of the third region 330 that absorbs the incident light different for each pixel, the wavelength band of the light absorbed by the third region 330 is changed for each pixel. Will be possible.
　第８のバリエーションによれば、光検出装置３００Ｈは、画素ごとに異なる波長帯域の光を検出することが可能となるため、より複雑なセンシングを行うことが可能である。 According to the eighth variation, the photodetector 300H can detect light in a different wavelength band for each pixel, so that more complicated sensing can be performed.
　（第９のバリエーション）
　図２０は、第９のバリエーションに係る光検出装置３００Ｉの構造を示す縦断面図である。 (9th variation)
FIG. 20 is a vertical cross-sectional view showing the structure of the photodetector 300I according to the ninth variation.
　図２０に示すように、光検出装置３００Ｉの第２面（すなわち、裏面と反対側の表面）には、回路部３８１を含む回路基板３８０と貼り合わせられた多層配線層３７０がさらに設けられてもよい。多層配線層３７０は、配線及びビアを含み、電極接合構造３８３（ＣｕＣｕ接合構造とも称される）を用いて、該配線及びビアと、回路基板３８０の絶縁層３８２に露出された電極とを電気的に接続する。 As shown in FIG. 20, on the second surface (that is, the surface opposite to the back surface) of the photodetector 300I, a multilayer wiring layer 370 bonded to the circuit board 380 including the circuit unit 381 is further provided. May be good. The multilayer wiring layer 370 includes wiring and vias, and uses an electrode bonding structure 383 (also referred to as a CuCu bonding structure) to electrically connect the wiring and vias and an electrode exposed to the insulating layer 382 of the circuit board 380. Connect to.
　第９のバリエーションによれば、光検出装置３００Ｉは、半導体基板の厚み方向に回路部３８１を含む回路基板３８０を積層することができるため、チップ面積をより小さくすることができる。 According to the ninth variation, the photodetector 300I can stack the circuit board 380 including the circuit unit 381 in the thickness direction of the semiconductor substrate, so that the chip area can be further reduced.
　（第１０のバリエーション）
　図２１Ａは、第１０のバリエーションに係る光検出装置３００Ｊの構造を示す縦断面図である。図２１Ｂは、図２１ＡのＡ－ＡＡ切断面における平面図である。 (10th variation)
FIG. 21A is a vertical cross-sectional view showing the structure of the photodetector 300J according to the tenth variation. 21B is a plan view of the AA cut surface of FIG. 21A.
　図２１Ａに示すように、光検出装置３００Ｊの第２面（すなわち、裏面と反対側の表面）には、回路部３８１を含む回路基板３８０と貼り合わせられた多層配線層３７０がさらに設けられてもよい。 As shown in FIG. 21A, a multilayer wiring layer 370 bonded to a circuit board 380 including a circuit unit 381 is further provided on the second surface (that is, the surface opposite to the back surface) of the photodetector 300J. May be good.
　ここで、多層配線層３７０の配線及びビアと、回路基板３８０の絶縁層３８２に露出された電極とを電気的に接続する電極接合構造３８３Ｊ（ＣｕＣｕ接合構造とも称される）は、第１電極３１１及び画素分離層３５１にて画定された画素領域の全体に広がって設けられてもよい。これによれば、電極接合構造３８３Ｊは、第３領域３３０を透過して多層配線層３７０側に入り込んだ光を反射することで、第３領域３３０における光電変換効率を向上させることができる。具体的には、図２１Ｂに示すように、電極接合構造３８３Ｊは、異なる電極に接続されたビア３７１、３７２の相互の電気的な離隔が維持されるように電極又は配線を分割しつつ、画素の全面に広がって設けられてもよい。 Here, the electrode bonding structure 383J (also referred to as CuCu bonding structure) that electrically connects the wiring and vias of the multilayer wiring layer 370 and the electrodes exposed on the insulating layer 382 of the circuit board 380 is the first electrode. It may be provided so as to spread over the entire pixel region defined by the 311 and the pixel separation layer 351. According to this, the electrode bonding structure 383J can improve the photoelectric conversion efficiency in the third region 330 by reflecting the light that has passed through the third region 330 and entered the multilayer wiring layer 370 side. Specifically, as shown in FIG. 21B, the electrode bonding structure 383J divides the electrodes or wirings so that the vias 371 and 372 connected to different electrodes are electrically separated from each other, and the pixels. It may be provided so as to spread over the entire surface of the.
　第１０のバリエーションによれば、光検出装置３００Ｊは、第３領域３３０での光電変換効率を向上させることができるため、入射光の検出感度を向上させることができる。 According to the tenth variation, the photodetector 300J can improve the photoelectric conversion efficiency in the third region 330, so that the detection sensitivity of the incident light can be improved.
　（第１１のバリエーション）
　図２２Ａは、第１１のバリエーションに係る光検出装置３００Ｋの構造を示す縦断面図である。図２２Ｂは、図２２ＡのＢ－ＢＢ切断面における平面図である。 (11th variation)
FIG. 22A is a vertical cross-sectional view showing the structure of the photodetector 300K according to the eleventh variation. FIG. 22B is a plan view of the B-BB cut surface of FIG. 22A.
　図２２Ａに示すように、光検出装置３００Ｋの第２面（すなわち、裏面と反対側の表面）には、回路部３８１を含む回路基板３８０と貼り合わせられた多層配線層３７０がさらに設けられてもよい。 As shown in FIG. 22A, on the second surface (that is, the surface opposite to the back surface) of the photodetector 300K, a multilayer wiring layer 370 bonded to the circuit board 380 including the circuit unit 381 is further provided. May be good.
　ここで、多層配線層３７０に含まれる配線３７３は、第１電極３１１及び画素分離層３５１にて画定された画素領域の全体に広がって設けられてもよい。これによれば、配線３７３は、第３領域３３０を透過して多層配線層３７０側に入り込んだ光を反射することで、第３領域３３０における光電変換効率を向上させることができる。具体的には、図２２Ｂに示すように、制御ゲート３６１と電気的に接続された配線３７３は、第２電極３２１の周囲を囲むように画素の全面に広がって設けられてもよい。 Here, the wiring 373 included in the multilayer wiring layer 370 may be provided so as to spread over the entire pixel region defined by the first electrode 311 and the pixel separation layer 351. According to this, the wiring 373 can improve the photoelectric conversion efficiency in the third region 330 by reflecting the light that has passed through the third region 330 and entered the multilayer wiring layer 370 side. Specifically, as shown in FIG. 22B, the wiring 373 electrically connected to the control gate 361 may be provided so as to extend over the entire surface of the pixel so as to surround the periphery of the second electrode 321.
　第１１のバリエーションによれば、光検出装置３００Ｋは、第３領域３３０での光電変換効率を向上させることができるため、入射光の検出感度を向上させることができる。 According to the eleventh variation, the photodetector 300K can improve the photoelectric conversion efficiency in the third region 330, so that the detection sensitivity of the incident light can be improved.
　（第１２のバリエーション）
　図２３は、第１２のバリエーションに係る光検出装置３００Ｌの構造を示す縦断面図である。 (12th variation)
FIG. 23 is a vertical cross-sectional view showing the structure of the photodetector 300L according to the twelfth variation.
　図２３に示すように、光検出装置３００Ｌの第１面（すなわち、光の入射面である裏面）には、散乱構造３５５Ｌがさらに設けられてもよい。散乱構造３５５Ｌは、入射光の波長以下の繰り返し周期で設けられた凹凸構造であり、例えば、モスアイ構造などである。散乱構造３５５Ｌは、光検出装置３００Ｌに入射する光を散乱させることで、入射光が第３領域３３０を透過してしまう可能性を低減することができる。なお、散乱構造３５５Ｌは、半導体基板の第１面を加工することで形成されてもよく、半導体基板の第１面の上に凹凸構造体を積層することで形成されてもよい。 As shown in FIG. 23, a scattering structure 355L may be further provided on the first surface (that is, the back surface which is the incident surface of light) of the photodetector 300L. The scattering structure 355L is a concavo-convex structure provided with a repeating period equal to or less than the wavelength of the incident light, and is, for example, a moth-eye structure. The scattering structure 355L can reduce the possibility that the incident light passes through the third region 330 by scattering the light incident on the photodetector 300L. The scattering structure 355L may be formed by processing the first surface of the semiconductor substrate, or may be formed by laminating a concavo-convex structure on the first surface of the semiconductor substrate.
　第１２のバリエーションによれば、光検出装置３００Ｌは、入射光を散乱させることで、第３領域３３０での光電変換効率を向上させることができる。したがって、光検出装置３００Ｌは、入射光の検出感度を向上させることができる。 According to the twelfth variation, the photodetector 300L can improve the photoelectric conversion efficiency in the third region 330 by scattering the incident light. Therefore, the photodetector 300L can improve the detection sensitivity of the incident light.
　（第１３のバリエーション）
　図２４Ａは、第１３のバリエーションに係る光検出装置３００Ｍの構造を示す縦断面図である。図２４Ｂは、図２４ＡのＣ－ＣＣ切断面における平面図である。 (13th variation)
FIG. 24A is a vertical cross-sectional view showing the structure of the photodetector 300M according to the thirteenth variation. FIG. 24B is a plan view of the C-CC cut plane of FIG. 24A.
　図２４Ａに示すように、光検出装置３００Ｍの第１面（すなわち、光の入射面である裏面）には、回折格子構造３５５Ｍがさらに設けられてもよい。回折格子構造３５５Ｍは、例えば、図２４Ｂに示すように、入射光の波長に応じた間隔で同心円状に複数の凹凸が形成された構造であってもよい。回折格子構造３５５Ｍは、光検出装置３００Ｍに入射する光を複数の経路に分岐させることで、画素内の所定の位置に入射光を集光させることができる。 As shown in FIG. 24A, a diffraction grating structure 355M may be further provided on the first surface (that is, the back surface which is the incident surface of light) of the photodetector 300M. As shown in FIG. 24B, for example, the diffraction grating structure 355M may have a structure in which a plurality of concentric irregularities are formed at intervals according to the wavelength of the incident light. The diffraction grating structure 355M can collect the incident light at a predetermined position in the pixel by branching the light incident on the photodetector 300M into a plurality of paths.
　第１３のバリエーションによれば、光検出装置３００Ｍは、所定の位置に入射光を集光させることで、第３領域３３０での光電変換効率を向上させることができる。したがって、光検出装置３００Ｍは、入射光の検出感度を向上させることができる。 According to the thirteenth variation, the photodetector 300M can improve the photoelectric conversion efficiency in the third region 330 by condensing the incident light at a predetermined position. Therefore, the photodetector 300M can improve the detection sensitivity of the incident light.
　（第１４のバリエーション）
　図２５は、第１４のバリエーションに係る光検出装置３００Ｎの構造を示す縦断面図である。 (14th variation)
FIG. 25 is a vertical cross-sectional view showing the structure of the photodetector 300N according to the 14th variation.
　図２５に示すように、光検出装置３００Ｎでは、第１領域３１０は、半導体基板の第１面の上に第１面絶縁層３５３を介して設けられた第１面電極３１３Ｎと電気的に接続されており、第１面電極３１３Ｎがカソード電極として機能する。第１面電極３１３Ｎは、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 As shown in FIG. 25, in the photodetector 300N, the first region 310 is electrically connected to the first surface electrode 313N provided on the first surface of the semiconductor substrate via the first surface insulating layer 353. The first surface electrode 313N functions as a cathode electrode. The first surface electrode 313N is, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided at.
　一方、第１電極３１１は、第１領域３１０と電気的に接続されておらず、第３領域３３０の内部に設けられた第２導電型の第２導電型領域３６３Ｎと電気的に接続される。これにより、第１電極３１１は、第２導電型領域３６３Ｎを介して、第３領域３３０の電位を制御することができる。したがって、第１電極３１１は、第３領域３３０に発生するポテンシャル障壁を制御する電極として機能することができる。 On the other hand, the first electrode 311 is not electrically connected to the first region 310, but is electrically connected to the second conductive type second conductive type region 363N provided inside the third region 330. .. As a result, the first electrode 311 can control the potential of the third region 330 via the second conductive type region 363N. Therefore, the first electrode 311 can function as an electrode for controlling the potential barrier generated in the third region 330.
　第１４のバリエーションによれば、光検出装置３００Ｎは、第３領域３３０に発生するポテンシャル障壁の制御性をより向上させることができるため、入射光の検出特性をより向上させることができる。 According to the fourteenth variation, the photodetector 300N can further improve the controllability of the potential barrier generated in the third region 330, so that the detection characteristics of the incident light can be further improved.
　（第１５のバリエーション）
　図２６は、第１５のバリエーションに係る光検出装置３００Ｏの構造を示す縦断面図である。 (15th variation)
FIG. 26 is a vertical cross-sectional view showing the structure of the photodetector 300O according to the fifteenth variation.
　図２６に示すように、光検出装置３００Ｏでは、半導体基板の第１面側に第２導電型（例えば、Ｐ型）の第１領域３１０Ｏが設けられ、第１面と反対側の第２面側に第１導電型（例えば、Ｎ型）の第２領域３２０Ｏが設けられる。このような場合、第１領域３１０Ｏと電気的に接続される第１電極３１１は、アノード電極として機能し、第２領域３２０Ｏと電気的に接続される第２電極３２１は、カソード電極として機能することになる。このような構成であっても、光検出装置３００Ｏは、画素ごとに入射光の検出を行うことが可能である。 As shown in FIG. 26, in the photodetector 300O, a second conductive type (for example, P type) first region 310O is provided on the first surface side of the semiconductor substrate, and a second surface opposite to the first surface is provided. A first conductive type (for example, N type) second region 320O is provided on the side. In such a case, the first electrode 311 electrically connected to the first region 310O functions as an anode electrode, and the second electrode 321 electrically connected to the second region 320O functions as a cathode electrode. It will be. Even with such a configuration, the photodetector 300O can detect the incident light for each pixel.
　第１５のバリエーションによれば、光検出装置３００Ｏは、導電型領域の極性の交換することができるため、構造設計の自由度を向上させることができる。 According to the fifteenth variation, the photodetector 300O can exchange the polarity of the conductive region, so that the degree of freedom in structural design can be improved.
　以上にて本実施形態に係る光検出装置３００の構造のバリエーションについて説明した。 The variation of the structure of the photodetector 300 according to the present embodiment has been described above.
　ただし、光検出装置３００のＤＣＲ（Ｄａｒｋ　Ｃｏｕｎｔ　Ｒａｔｅ）を抑制する観点からは、第１領域３１０と第２領域３２０との距離が確保されていることが望ましい。すなわち、第２領域３２０及び第１電極３１１の半導体基板の厚み方向における形成深さには望ましい関係性が存在する。ここで、図２７を参照して、かかる関係性について説明する。図２７は、第２領域３２０及び第１電極３１１の形成深さについて説明する縦断面図である。 However, from the viewpoint of suppressing the DCR (Dark Count Rate) of the photodetector 300, it is desirable that the distance between the first region 310 and the second region 320 is secured. That is, there is a desirable relationship between the formation depths of the second region 320 and the first electrode 311 in the thickness direction of the semiconductor substrate. Here, such a relationship will be described with reference to FIG. 27. FIG. 27 is a vertical cross-sectional view illustrating the formation depth of the second region 320 and the first electrode 311.
　図２７に示すように、半導体基板の第２面からの第２領域３２０の形成深さをｈ＿Ｐ＋とし、半導体基板の第２面からの第１電極３１１の底面までの形成深さをｈ＿Ｄとし、半導体基板の第２面から上部第１電極３１２の底面までの形成深さ（すなわち、半導体基板の第２面から第１面までの距離）をｈ＿Ｆとする。第１領域３１０と第２領域３２０との距離を確保するためには、ｈ＿Ｄは、ｈ＿Ｐ＋及びｈ＿Ｆに対して以下の関係性を有することが望ましい。
 
　ｈ＿Ｐ＋　＜　ｈ＿Ｄ　＜　ｈ＿Ｆ
  As shown in FIG. 27, the formation depth of the second region 320 from the second surface of the semiconductor substrate is h_P +, and the formation depth from the second surface of the semiconductor substrate to the bottom surface of the first electrode 311 is h_D. Let h_F be the formation depth from the second surface of the semiconductor substrate to the bottom surface of the upper first electrode 312 (that is, the distance from the second surface to the first surface of the semiconductor substrate). In order to secure the distance between the first region 310 and the second region 320, it is desirable that h_D has the following relationship with h_P + and h_F.

h_P + <h_D <h_F
　第２領域３２０の形成深さｈ＿Ｐ＋、及び第１電極３１１の形成深さｈ＿Ｄが上記の関係性を有する場合、光検出装置３００は、ＤＣＲ（Ｄａｒｋ　Ｃｏｕｎｔ　Ｒａｔｅ）を抑制することができる。なお、第１電極３１１の形成深さｈ＿Ｄが過度の大きい場合、製造工程のプロセス精度が低下し、製造歩留まりが低下する可能性がある。したがって、第１電極３１１の形成深さｈ＿Ｄは、所望のプロセス精度を維持できる範囲でより大きく設定されることが望ましい。 When the formation depth h_P + of the second region 320 and the formation depth h_D of the first electrode 311 have the above-mentioned relationship, the photodetector 300 can suppress the DCR (Dark Count Rate). If the formation depth h_D of the first electrode 311 is excessively large, the process accuracy of the manufacturing process may be lowered, and the manufacturing yield may be lowered. Therefore, it is desirable that the formation depth h_D of the first electrode 311 is set larger within a range in which the desired process accuracy can be maintained.
　（動作例）
　次に、図２８～図３０Ｃを参照して、本実施形態に係る光検出装置３００のＴｏＦ（Ｔｉｍｅ　ｏｆ　Ｆｌｉｇｈｔ）センサとしての動作例について説明する。図２８は、本実施形態に係る光検出装置３００のＴｏＦセンサ動作の一例を示すタイミングチャート図である。図２９は、ＴｏＦセンサに用いられる光源を説明する説明図である。図３０Ａは、図２８の（１）のタイミングにおける光検出装置３００の状態を説明する縦断面図であり、図３０Ｂは、図２８の（２）のタイミングにおける光検出装置３００の状態を説明する縦断面図であり、図３０Ｃは、図２８の（３）のタイミングにおける光検出装置３００の状態を説明する縦断面図である。 (Operation example)
Next, an operation example of the photodetector 300 according to the present embodiment as a ToF (Time of Flight) sensor will be described with reference to FIGS. 28 to 30C. FIG. 28 is a timing chart showing an example of the operation of the ToF sensor of the photodetector 300 according to the present embodiment. FIG. 29 is an explanatory diagram illustrating a light source used in the ToF sensor. FIG. 30A is a vertical cross-sectional view illustrating the state of the photodetector 300 at the timing of FIG. 28 (1), and FIG. 30B describes the state of the photodetector 300 at the timing of FIG. 28 (2). It is a vertical cross-sectional view, and FIG. 30C is a vertical cross-sectional view illustrating a state of the photodetector 300 at the timing of FIG. 28 (3).
　図２８及び図３０Ａに示すように、まず、図２８の（１）のタイミングで、スイッチトランジスタのゲートに印加される電圧ＶＳＷに正電圧を印加することで、スイッチトランジスタをオン状態とする。続いて、第２電極３２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。このとき、第１電極３１１に印加される電圧Ｖｃは、０Ｖであるため、光検出装置３００の第１領域３１０及び第２領域３２０の間には、逆バイアスが印加されることになる。なお、制御ゲート３６１に印加される電圧Ｖｇは、負電圧（例えば、－１Ｖ）に設定する。 As shown in FIGS. 28 and 30A, first, at the timing of (1) in FIG. 28, a positive voltage is applied to the voltage VSW applied to the gate of the switch transistor to turn on the switch transistor. Subsequently, the voltage Va applied to the second electrode 321 is set to a negative voltage (for example, -1V). At this time, since the voltage Vc applied to the first electrode 311 is 0 V, a reverse bias is applied between the first region 310 and the second region 320 of the photodetector 300. The voltage Vg applied to the control gate 361 is set to a negative voltage (for example, -1V).
　ここで、図２８、図２９、及び図３０Ｂに示すように、図２８の（２）のタイミングで、レーザダイオード又はＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）などの光源ＬＤにパルス状の負電圧Ｖｌｉｇｈｔを印加することで、対象物にパルス光を照射する。同時に、第２電極３２１に印加される電圧Ｖａを正電圧（例えば、＋１Ｖ）とすることで、光検出装置３００の第１領域３１０及び第２領域３２０の間に順バイアスを印加する。また、制御ゲート３６１に印加される電圧Ｖｇを正電圧（例えば、＋１Ｖ）に設定する。 Here, as shown in FIGS. 28, 29, and 30B, a pulsed negative voltage V light is applied to the light source LD such as a laser diode or an LED (Light Emitting Diode) at the timing of (2) in FIG. 28. By doing so, the object is irradiated with pulsed light. At the same time, by setting the voltage Va applied to the second electrode 321 to a positive voltage (for example, + 1V), a forward bias is applied between the first region 310 and the second region 320 of the photodetector 300. Further, the voltage Vg applied to the control gate 361 is set to a positive voltage (for example, + 1V).
　その後、対象物にて反射されたパルス光が光検出装置３００に入射し、第２電極３２１から出力される電流値が（２）のタイミングから遅延して増加する。したがって、光検出装置３００は、光源ＬＤの発光タイミングｔ２と、光検出の遅延時間ｔ１との差を算出することで、対象物までの距離を算出することができる。 After that, the pulsed light reflected by the object is incident on the photodetector 300, and the current value output from the second electrode 321 is delayed from the timing of (2) and increases. Therefore, the photodetector 300 can calculate the distance to the object by calculating the difference between the light emission timing t2 of the light source LD and the light detection delay time t1.
　さらに、図２８及び図３０Ｃに示すように、図２８の（３）のタイミングで第２電極３２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。これにより、光検出装置３００の第１領域３１０及び第２領域３２０の間には逆バイアスが印加されるため、光検出装置３００の状態がリセットされる。なお、制御ゲート３６１に印加される電圧Ｖｇも同様に負電圧（例えば、－１Ｖ）に設定してもよい。 Further, as shown in FIGS. 28 and 30C, the voltage Va applied to the second electrode 321 at the timing of (3) in FIG. 28 is set to a negative voltage (for example, -1V). As a result, a reverse bias is applied between the first region 310 and the second region 320 of the photodetector 300, so that the state of the photodetector 300 is reset. The voltage Vg applied to the control gate 361 may also be set to a negative voltage (for example, -1V).
　以上の動作を１フレームとして繰り返すことで、光検出装置３００は対象物までの距離を１フレームごとに検出することができる。 By repeating the above operation as one frame, the photodetector 300 can detect the distance to the object for each frame.
　（変形例）
　続いて、図３１Ａ～図３４を参照して、本実施形態に係る光検出装置３００の第１及び第２の変形例について説明する。 (Modification example)
Subsequently, first and second modified examples of the photodetector 300 according to the present embodiment will be described with reference to FIGS. 31A to 34.
　（第１の変形例）
　図３１Ａは、第１の変形例に係る光検出装置３００Ｐの構造を示す縦断面図である。図３１Ｂは、第１の変形例に係る光検出装置３００Ｐの構造を示す第２面側から見た平面図である。図３２は、第１の変形例に係る光検出装置３００Ｐにおける駆動電圧例を示すタイミングチャート図である。 (First modification)
FIG. 31A is a vertical cross-sectional view showing the structure of the photodetector 300P according to the first modification. FIG. 31B is a plan view of the photodetector 300P according to the first modification as viewed from the second surface side. FIG. 32 is a timing chart showing an example of a drive voltage in the photodetector 300P according to the first modification.
　図３１Ａに示すように、光検出装置３００Ｐでは、制御ゲート３６１及びゲート絶縁膜３６２に替えて、半導体基板の第２面側にポテンシャル制御領域３６５が設けられる。光検出装置３００Ｐは、ポテンシャル制御領域３６５に電圧を印加することで、第２領域３２０に隣接する領域に発生するポテンシャル障壁を制御することができる。 As shown in FIG. 31A, in the photodetector 300P, a potential control region 365 is provided on the second surface side of the semiconductor substrate instead of the control gate 361 and the gate insulating film 362. The photodetector 300P can control a potential barrier generated in a region adjacent to the second region 320 by applying a voltage to the potential control region 365.
　ポテンシャル制御領域３６５は、第１導電型の領域（例えば、Ｎ＋層）であり、絶縁層３６６を挟んで第２領域３２０の周囲を囲むように設けられる。すなわち、図３１Ｂに示すように、半導体基板の第２面側には、第１電極３１１及び画素分離層３５１にて画定された領域の略中央に島状に第２領域３２０が設けられる。さらに、第２領域３２０の周囲を囲むように絶縁層３６６が設けられ、絶縁層３６６の周囲を囲むようにポテンシャル制御領域３６５が設けられる。 The potential control region 365 is a first conductive type region (for example, N + layer), and is provided so as to surround the second region 320 with the insulating layer 366 interposed therebetween. That is, as shown in FIG. 31B, on the second surface side of the semiconductor substrate, the second region 320 is provided in an island shape substantially in the center of the region defined by the first electrode 311 and the pixel separation layer 351. Further, an insulating layer 366 is provided so as to surround the periphery of the second region 320, and a potential control region 365 is provided so as to surround the periphery of the insulating layer 366.
　このような構成であっても、図３２に示すように、ポテンシャル制御領域３６５に印加される電圧Ｖｇを制御ゲート３６１と同様に制御することで、光検出装置３００Ｐは入射光の検出を行うことができる。 Even with such a configuration, as shown in FIG. 32, the photodetector 300P detects the incident light by controlling the voltage Vg applied to the potential control region 365 in the same manner as the control gate 361. Can be done.
　（第２の変形例）
　図３３Ａは、第２の変形例に係る光検出装置３００Ｑの構造を示す第２面側から見た平面図である。図３３Ｂは、図３３ＡのＡ－ＡＡ切断面における光検出装置３００Ｑの構造を示す縦断面図である。図３３Ｃは、図３３ＡのＢ－ＢＢ切断面における光検出装置３００Ｑの構造を示す縦断面図である。 (Second modification)
FIG. 33A is a plan view seen from the second surface side showing the structure of the photodetector 300Q according to the second modification. FIG. 33B is a vertical cross-sectional view showing the structure of the photodetector 300Q on the AA cut surface of FIG. 33A. FIG. 33C is a vertical cross-sectional view showing the structure of the photodetector 300Q on the B-BB cut surface of FIG. 33A.
　図３３Ａ～図３３Ｃに示すように、第２の変形例に係る光検出装置３００Ｑは、第１の変形例に係る光検出装置３００Ｐに対して、転送ゲート及びフローティングディフュージョンをさらに備え、一般的なフォトダイオード（ＰＤ）としても機能することができる点が異なる。 As shown in FIGS. 33A to 33C, the photodetector 300Q according to the second modification further includes a transfer gate and a floating diffusion with respect to the photodetector 300P according to the first modification, and is general. The difference is that it can also function as a photodiode (PD).
　具体的には、図３３Ａ及び図３３Ｂに示すように、光検出装置３００Ｑは、第１の変形例に係る光検出装置３００Ｐと同様に、第１領域３１０、第３領域３３０、第２領域３２０、絶縁層３６６、ポテンシャル制御領域３６５、及びポテンシャル制御領域３６５に電圧を印加する電極３６７を備える。これにより、光検出装置３００Ｑは、半導体基板の面内の第１方向（図３３Ａでは縦方向）において、ＤＰＤセンサとして機能することができる。 Specifically, as shown in FIGS. 33A and 33B, the photodetector 300Q has a first region 310, a third region 330, and a second region 320, similarly to the photodetector 300P according to the first modification. The insulating layer 366, the potential control region 365, and the electrode 367 that applies a voltage to the potential control region 365 are provided. As a result, the photodetector 300Q can function as a DPD sensor in the first direction (vertical direction in FIG. 33A) in the plane of the semiconductor substrate.
　また、図３３Ａ及び図３３Ｃに示すように、光検出装置３００Ｑは、第１領域３１０、第３領域３３０、第２領域３２０、第１導電型領域３９１、転送ゲートＴＲＧ、第２導電型のフローティングディフュージョンＦＤ、及び取出電極３９３を備える。これにより、光検出装置３００Ｑは、半導体基板の面内の第１方向と直交する第２方向（図３３Ａでは横方向）において、通常のＰＤとして機能することができる。 Further, as shown in FIGS. 33A and 33C, the photodetector 300Q has a first region 310, a third region 330, a second region 320, a first conductive region 391, a transfer gate TRG, and a floating second conductive type. It includes a diffusion FD and an extraction electrode 393. As a result, the photodetector 300Q can function as a normal PD in the second direction (lateral direction in FIG. 33A) orthogonal to the first direction in the plane of the semiconductor substrate.
　具体的には、ゲート絶縁膜３９２を介して半導体基板の第２面の上に設けられた転送ゲートＴＲＧに電圧を印加することで、第１導電型領域３９１を介して、第２領域３２０からフローティングディフュージョンＦＤに電荷を転送することができる。フローティングディフュージョンＦＤに転送された電荷は、例えば、取出電極３９３から画素回路等に取り出される。 Specifically, by applying a voltage to the transfer gate TRG provided on the second surface of the semiconductor substrate via the gate insulating film 392, from the second region 320 via the first conductive type region 391. Charges can be transferred to the floating diffusion FD. The electric charge transferred to the floating diffusion FD is taken out from the take-out electrode 393 to a pixel circuit or the like, for example.
　なお、画素回路を構成する画素トランジスタは、例えば、画素分離層３５１に隣接して設けられた画素トランジスタ領域Ｔｒに設けられてもよい。例えば、画素トランジスタ領域Ｔｒには、画素回路を構成するリセットトランジスタ、アンプトランジスタ、選択トランジスタ、又はスイッチトランジスタの少なくともいずれか１つ以上が設けられてもよい。画素トランジスタ領域Ｔｒに設けられたトランジスタの各々は、例えば、半導体基板を掘り込んで設けられた絶縁層によって互いに電気的に絶縁されてもよい。 Note that the pixel transistors constituting the pixel circuit may be provided, for example, in the pixel transistor region Tr provided adjacent to the pixel separation layer 351. For example, at least one or more of a reset transistor, an amplifier transistor, a selection transistor, or a switch transistor constituting a pixel circuit may be provided in the pixel transistor region Tr. Each of the transistors provided in the pixel transistor region Tr may be electrically insulated from each other by, for example, an insulating layer provided by digging a semiconductor substrate.
　第２の変形例に係る光検出装置３００Ｑは、例えば、図３４で等価回路を示す画素回路を備えてもよい。図３４は、ＤＰＤセンサ及びＰＤとして機能する光検出装置３００Ｑが備える画素回路の等価回路の一例を示す回路図である。なお、ＤＰＤ／ＰＤは、上述した第１領域３１０、第３領域３３０、及び第２領域３２０が積層されたＰＩＮダイオード構造の光電変換部を示す。 The photodetector 300Q according to the second modification may include, for example, a pixel circuit showing an equivalent circuit in FIG. 34. FIG. 34 is a circuit diagram showing an example of an equivalent circuit of a pixel circuit included in the DPD sensor and the photodetector 300Q that functions as a PD. Note that DPD / PD indicates a photoelectric conversion unit having a PIN diode structure in which the above-mentioned first region 310, third region 330, and second region 320 are laminated.
　図３４に示すように、ＤＰＤセンサ側の画素回路としては、光電変換部ＤＰＤは、スイッチトランジスタＳＷを介して電源Ｖａと電気的に接続する。また、ＰＤ側の画素回路としては、光電変換部ＰＤは、転送トランジスタＴＲＧを介して、フローティングディフュージョンＦＤに電気的に接続される。 As shown in FIG. 34, as a pixel circuit on the DPD sensor side, the photoelectric conversion unit DPD is electrically connected to the power supply Va via the switch transistor SW. Further, as a pixel circuit on the PD side, the photoelectric conversion unit PD is electrically connected to the floating diffusion FD via the transfer transistor TRG.
　さらに、フローティングディフュージョンＦＤには、さらにリセットトランジスタＲＳＴを介して電源Ｖｄが接続され、かつアンプトランジスタＡＭＰのゲートが接続される。アンプトランジスタＡＭＰのドレインは、電源Ｖｄに接続され、アンプトランジスタＡＭＰのソースは、選択トランジスタＳＥＬを介して外部出力Ｏｕｔｐｕｔに接続される。なお、ＤＰＤセンサ側の電源Ｖａと、ＰＤ側の電源Ｖｄとは、互いに異なる電源であってもよく、同一の電源であってもよい。このような画素回路を備えることにより、第２の変形例に係る光検出装置３００Ｑは、ＤＰＤセンサ及びＰＤの両方として機能することが可能である。 Further, the power supply Vd is further connected to the floating diffusion FD via the reset transistor RST, and the gate of the amplifier transistor AMP is also connected. The drain of the amplifier transistor AMP is connected to the power supply Vd, and the source of the amplifier transistor AMP is connected to the external output Output via the selection transistor SEL. The power supply Va on the DPD sensor side and the power supply Vd on the PD side may be different power supplies or the same power supply. By providing such a pixel circuit, the photodetector 300Q according to the second modification can function as both a DPD sensor and a PD.
　＜２．第２の実施形態＞
　（基本構造）
　次に、図３５～図３８を参照して、本開示の第２の実施形態に係る光検出装置の基本構造について説明する。 <2. Second embodiment>
(Basic structure)
Next, with reference to FIGS. 35 to 38, the basic structure of the photodetector according to the second embodiment of the present disclosure will be described.
　まず、図３５及び図３６を参照して、本実施形態に係る光検出装置の基本特性について説明する。本実施形態に係る光検出装置は、印加されるバイアスを逆バイアスから順バイアスに反転させた際に順方向電流が流れるまでの遅延時間を計測することによって、入射する光を検出する、いわゆるＤＰＤセンサである。図３５は、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後の電荷の移動を時系列で示す模式図である。図３６は、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後のバンド構造の変化を時系列で示すグラフ図である。 First, the basic characteristics of the photodetector according to the present embodiment will be described with reference to FIGS. 35 and 36. The photodetector according to the present embodiment detects incident light by measuring the delay time until a forward current flows when the applied bias is reversed from a reverse bias to a forward bias, that is, a so-called DPD. It is a sensor. FIG. 35 is a schematic diagram showing the movement of electric charges after reversing the bias applied to the photodetector from the reverse bias to the forward bias in chronological order. FIG. 36 is a graph showing changes in the band structure in chronological order after the bias applied to the photodetector is reversed from the reverse bias to the forward bias.
　図３５及び図３６の（１）に示すように、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した場合、光検出装置では、まず、カソード電極（第１電極）からＰ＋層（第２領域）の周囲のバンド構造の落ち込み（ディップとも称される）に向かって電子ｅが流入する。 As shown in (1) of FIGS. 35 and 36, when the bias applied to the photodetector is reversed from the reverse bias to the forward bias, the photodetector first starts with the cathode electrode (first electrode) to the P + layer. Electrons e flow toward the dip (also called a dip) of the band structure around the (second region).
　これにより、図３５及び図３６の（２）に示すように、Ｐ＋層（第２領域）の周囲のポテンシャル障壁が低下する（ディップの大きさが減少する）ため、Ｐ＋層（第２領域）から流出する正孔ｈが増加する。 As a result, as shown in (2) of FIGS. 35 and 36, the potential barrier around the P + layer (second region) is lowered (the size of the dip is reduced), so that the P + layer (second region) Hole h flowing out from is increased.
　さらに、図３５及び図３６の（３）に示すように、Ｐ＋層（第２領域）からの正孔ｈの流出によって、Ｎ＋層（第１領域）の周囲のポテンシャル障壁が低下するため、Ｎ＋層（第１領域）からＰ＋層（第２領域）の周囲への電子ｅの流れがさらに増加する。その後も、Ｐ＋層（第２領域）からの正孔ｈの流出、及びＮ＋層（第１領域）からの電子ｅの流出が増加することで、Ｎ＋層（第１領域）及びＰ＋層（第２領域）の周囲のポテンシャル障壁が互いに低下する。 Further, as shown in (3) of FIGS. 35 and 36, the outflow of holes h from the P + layer (second region) lowers the potential barrier around the N + layer (first region), so that N + The flow of electrons e from the layer (first region) to the periphery of the P + layer (second region) is further increased. After that, the outflow of holes h from the P + layer (second region) and the outflow of electrons e from the N + layer (first region) increase, so that the N + layer (first region) and the P + layer (first region) are increased. The potential barriers around the two regions) decrease with each other.
　その後、図３５及び図３６の（４）に示すように、Ｐ＋層（第２領域）及びＮ＋層（第１領域）の間のポテンシャル障壁が消失し、光検出装置は、カソード電極（第１電極）及びアノード電極（第２電極）の間に順方向電流が流れる定常状態に達する。 After that, as shown in (4) of FIGS. 35 and 36, the potential barrier between the P + layer (second region) and the N + layer (first region) disappeared, and the photodetector used the cathode electrode (first region). A steady state is reached in which a forward current flows between the electrode) and the anode electrode (second electrode).
　本実施形態に係る光検出装置では、逆バイアスから順バイアスに反転してから上記の挙動によって定常状態に達するまでの時間が入射光の強度によって変化する。これは、入射光の光電変換にて生じた電子がカソード電極（第１電極）からＰ＋層（第２領域）の周囲のディップへの電子ｅの流入を加速させるためである。したがって、本実施形態に係る光検出装置は、印加バイアスを逆バイアスから順バイアスに反転させた際に、順方向電流が流れるまでの遅延時間を計測することによって、入射する光を検出することができる。 In the photodetector according to the present embodiment, the time from inversion from reverse bias to forward bias to reaching a steady state by the above behavior changes depending on the intensity of incident light. This is because the electrons generated by the photoelectric conversion of the incident light accelerate the inflow of the electrons e from the cathode electrode (first electrode) to the dip around the P + layer (second region). Therefore, the photodetector according to the present embodiment can detect incident light by measuring the delay time until the forward current flows when the applied bias is reversed from the reverse bias to the forward bias. it can.
　続いて、図３７及び図３８を参照して、本開示の第２の実施形態に係る光検出装置の基本構造について説明する。図３７は、本実施形態に係る光検出装置４００の基本構造を示す縦断面図であり、図３８は、本実施形態に係る光検出装置４００の基本構造を示す第１面側からの透過平面図である。 Subsequently, with reference to FIGS. 37 and 38, the basic structure of the photodetector according to the second embodiment of the present disclosure will be described. FIG. 37 is a vertical sectional view showing the basic structure of the photodetector 400 according to the present embodiment, and FIG. 38 is a transmission plane from the first surface side showing the basic structure of the photodetector 400 according to the present embodiment. It is a figure.
　図３７に示すように、光検出装置４００は、例えば、第１領域４１０と、第２領域４２０と、第３領域４３０と、第１電極４１１と、ビア４１２と、第１面絶縁層４５１と、画素分離層４５０と、貫通絶縁層４５２と、第３電極４７１と、電位制御領域４７３と、第４電極４７２と、リセット領域４７４と、第２電極４２１と、制御ゲート４６１と、ゲート絶縁膜４６２とを備える。 As shown in FIG. 37, the photodetector 400 includes, for example, a first region 410, a second region 420, a third region 430, a first electrode 411, a via 412, and a first surface insulating layer 451. , Pixel separation layer 450, through insulating layer 452, third electrode 471, potential control region 473, fourth electrode 472, reset region 474, second electrode 421, control gate 461, and gate insulating film. It is equipped with 462.
　第１領域４１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域４２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域４３０は、シリコン（Ｓｉ）などの半導体基板の第１領域４１０と第２領域４２０との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 410 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 420 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The third region 430 is a third conductive type region (for example, layer i) provided between the first region 410 and the second region 420 of a semiconductor substrate such as silicon (Si).
　第１電極４１１は、半導体基板の第１面の上に第１面絶縁層４５１を介して設けられ、第１面絶縁層４５１を貫通するビア４１２等を介して第１領域４１０と電気的に接続する。第１電極４１１は、例えば、カソード電極として機能する。第１電極４１１は、例えば、画素同士の境界に設けられた貫通絶縁層４５２を跨ぐように設けられ、画素ごとに設けられたビア４１２にて、各画素の第１領域４１０と電気的に接続される。すなわち、第１電極４１１は、各画素の第１領域４１０に共通の電位を供給する共通電極である。 The first electrode 411 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 451 and is electrically connected to the first region 410 via the via 412 or the like penetrating the first surface insulating layer 451. Connecting. The first electrode 411 functions as, for example, a cathode electrode. The first electrode 411 is provided, for example, so as to straddle the through insulating layer 452 provided at the boundary between pixels, and is electrically connected to the first region 410 of each pixel by a via 412 provided for each pixel. Will be done. That is, the first electrode 411 is a common electrode that supplies a common potential to the first region 410 of each pixel.
　第３電極４７１及び第４電極４７２は、各画素の境界にて半導体基板の第２面から半導体基板の厚み方向に延在して設けられ、第３電極４７１及び第４電極４７２よりも幅が小さい貫通絶縁層４５２と底面にて当接する。第３電極４７１及び第４電極４７２は、画素領域の境界に沿って、互いに対向するように設けられてもよい。貫通絶縁層４５２は、第３電極４７１及び第４電極４７２よりも幅が小さく、第３電極４７１及び第４電極４７２の底面から半導体基板の第２面まで半導体基板の厚み方向に延在して設けられる。 The third electrode 471 and the fourth electrode 472 are provided extending from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate at the boundary of each pixel, and are wider than the third electrode 471 and the fourth electrode 472. It abuts on the bottom surface with a small penetrating insulating layer 452. The third electrode 471 and the fourth electrode 472 may be provided so as to face each other along the boundary of the pixel region. The through insulating layer 452 has a width smaller than that of the third electrode 471 and the fourth electrode 472, and extends from the bottom surface of the third electrode 471 and the fourth electrode 472 to the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate. It is provided.
　画素分離層４５０は、第３電極４７１及び第４電極４７２の各々の側面に設けられる。これにより、画素分離層４５０は、第３電極４７１及び第４電極４７２の上部に設けられた貫通絶縁層４５２と共に、半導体基板の面内方向に隣接して設けられた各画素の光検出装置４００の各々を互いに電気的に離隔することができる。 The pixel separation layer 450 is provided on each side surface of the third electrode 471 and the fourth electrode 472. As a result, the pixel separation layer 450 is provided with a through-insulation layer 452 provided above the third electrode 471 and the fourth electrode 472, and the photodetector 400 for each pixel provided adjacent to the semiconductor substrate in the in-plane direction. Each of them can be electrically separated from each other.
　ここで、第３電極４７１及び第４電極４７２の幅は、貫通絶縁層４５２の幅よりも大きいため、第３電極４７１及び第４電極４７２の貫通絶縁層４５２と当接する底面の一部は、貫通絶縁層４５２にて覆われず、第３領域４３０側に露出する。したがって、第３電極４７１は、第３領域４３０側に露出する底面の一部にて、第３領域４３０の内部に設けられた電位制御領域４７３と電気的に接続することができる。また、第４電極４７２は、第３領域４３０側に露出する底面の一部にて、第３領域４３０の内部に設けられたリセット領域４７４と電気的に接続することができる。 Here, since the width of the third electrode 471 and the fourth electrode 472 is larger than the width of the through insulating layer 452, a part of the bottom surface of the third electrode 471 and the fourth electrode 472 that comes into contact with the through insulating layer 452 is formed. It is not covered by the through insulating layer 452 and is exposed on the third region 430 side. Therefore, the third electrode 471 can be electrically connected to the potential control region 473 provided inside the third region 430 at a part of the bottom surface exposed to the third region 430 side. Further, the fourth electrode 472 can be electrically connected to the reset region 474 provided inside the third region 430 at a part of the bottom surface exposed to the third region 430 side.
　電位制御領域４７３は、第２導電型の領域であり、第３電極４７１と電気的に接続するように設けられる。電位制御領域４７３は、第３電極４７１から負電圧を印加されることで、第３領域４３０の電位を制御することができる。これにより、第３電極４７１及び電位制御領域４７３は、第３領域４３０に発生するポテンシャル障壁の大きさを制御することができる。 The potential control region 473 is a second conductive type region and is provided so as to be electrically connected to the third electrode 471. The potential control region 473 can control the potential of the third region 430 by applying a negative voltage from the third electrode 471. As a result, the third electrode 471 and the potential control region 473 can control the size of the potential barrier generated in the third region 430.
　リセット領域４７４は、第１導電型の領域であり、第４電極４７２と電気的に接続するように設けられる。リセット領域４７４は、第４電極４７２から正電圧を印加されることで、第３領域４３０の内部に残存する電荷を排出することができる。これにより、第４電極４７２及びリセット領域４７４は、例えば、光検出装置４００にて入射光の検出が終了した際に、第３領域４３０の内部に残存する電荷をより確実に排出し、光検出装置４００にて残像が発生することを抑制することができる。 The reset region 474 is a first conductive type region and is provided so as to be electrically connected to the fourth electrode 472. By applying a positive voltage from the fourth electrode 472 to the reset region 474, the electric charge remaining inside the third region 430 can be discharged. As a result, the fourth electrode 472 and the reset region 474 more reliably discharge the electric charge remaining inside the third region 430 when the detection of the incident light is completed by the photodetector 400, for example, and the photodetection It is possible to suppress the generation of afterimages in the device 400.
　電位制御領域４７３及びリセット領域４７４は、図３８に示す平面配置にて設けられてもよい。例えば、電位制御領域４７３は、矩形形状の画素領域の一方の辺に沿って設けられ、リセット領域４７４は、矩形形状の画素領域の一方の辺と対向する他方の辺に沿って設けられてもよい。 The potential control region 473 and the reset region 474 may be provided in the planar arrangement shown in FIG. 38. For example, the potential control region 473 may be provided along one side of the rectangular pixel region, and the reset region 474 may be provided along the other side facing one side of the rectangular pixel region. Good.
　第２電極４２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域４２０と電気的に接続する。第２電極４２１は、例えば、アノード電極として機能し、半導体基板の第２面側から配線層に電気的に接続される。 The second electrode 421 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 420. The second electrode 421 functions as, for example, an anode electrode and is electrically connected to the wiring layer from the second surface side of the semiconductor substrate.
　制御ゲート４６１は、半導体基板の第２面の上にゲート絶縁膜４６２を介して設けられるゲート電極である。制御ゲート４６１は、電圧印加によって、第３領域４３０におけるポテンシャル障壁を制御するために設けられる。 The control gate 461 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 462. The control gate 461 is provided to control the potential barrier in the third region 430 by applying a voltage.
　第１電極４１１、第２電極４２１、第３電極４７１、第４電極４７２、ビア４１２、及び制御ゲート４６１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。画素分離層４５０、貫通絶縁層４５２、第１面絶縁層４５１、及びゲート絶縁膜４６２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 411, the second electrode 421, the third electrode 471, the fourth electrode 472, the via 412, and the control gate 461 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti). , Or a metal such as tantalum (Ta), polysilicon (poly-Si), or other conductive material. The pixel separation layer 450, the through insulating layer 452, the first surface insulating layer 451 and the gate insulating film 462 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or so-called low-k. It may be provided by an insulator such as a material.
　本実施形態に係る光検出装置４００は、裏面（すなわち、第１面）照射型のＣＭＯＳ（Ｃｏｍｐｌｅｍｅｎｔａｒｙ　ＭＯＳ）イメージセンサとして設けられることで、光入射面である裏面側の配線を削減し、裏面側の開口率を増加させることができる。具体的には、光検出装置４００は、第３領域４３０の電位を制御する第３電極４７１、及び第３領域４３０から電荷を排出する第４電極４７２を半導体基板の第２面から半導体基板の厚み方向に延在させて設けることができる。したがって、光検出装置４００は、第３領域４３０の電位を制御する第３電極４７１、及び第３領域４３０から電荷を排出する第４電極４７２を設けた場合であっても、光入射面である裏面側に設けられる配線を削減し、かつ画素面積が増加することを防止することができる。 The photodetector 400 according to the present embodiment is provided as a back surface (that is, the first surface) irradiation type CMOS (Complementary MOS) image sensor, thereby reducing the wiring on the back surface side which is the light incident surface and reducing the wiring on the back surface side. The aperture ratio of the can be increased. Specifically, the photodetector 400 uses the third electrode 471 that controls the potential of the third region 430 and the fourth electrode 472 that discharges charges from the third region 430 from the second surface of the semiconductor substrate to the semiconductor substrate. It can be provided so as to extend in the thickness direction. Therefore, the light detection device 400 is a light incident surface even when the third electrode 471 that controls the potential of the third region 430 and the fourth electrode 472 that discharges the electric charge from the third region 430 are provided. It is possible to reduce the wiring provided on the back surface side and prevent the pixel area from increasing.
　（バリエーション）
　次に、図３９～図４３Ｂを参照して、本実施形態に係る光検出装置４００の構造のバリエーションについて説明する。 (variation)
Next, with reference to FIGS. 39 to 43B, variations in the structure of the photodetector 400 according to the present embodiment will be described.
　（第１のバリエーション）
　図３９は、第１のバリエーションに係る光検出装置４００Ａの構成を説明する第２面側から見た平面図である。図３９では、光検出装置４００Ａの構成のうち着目した構成についてのみ示す。 (First variation)
FIG. 39 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400A according to the first variation. FIG. 39 shows only the configuration of interest in the configuration of the photodetector 400A.
　図３９に示すように、第３電極４７１及び電位制御領域４７３は、矩形形状の画素領域の一方の辺に沿って設けられ、第４電極４７２及びリセット領域４７４は、矩形形状の画素領域の一方の辺と対向する他方の辺に沿って設けられてもよい。 As shown in FIG. 39, the third electrode 471 and the potential control region 473 are provided along one side of the rectangular pixel region, and the fourth electrode 472 and the reset region 474 are one of the rectangular pixel regions. It may be provided along the other side facing the side of.
　第３電極４７１及び第４電極４７２の各々は、画素ごとに独立して設けられてもよい。各画素の第３電極４７１は、第３電極４７１の延在方向に延在する第２面側に設けられた配線にて互いに電気的に接続されてもよい。同様に、各画素の第４電極４７２は、第４電極４７２の延在方向に延在する第２面側に設けられた配線にて互いに電気的に接続されてもよい。各画素の第３電極４７１を電気的に接続する配線、及び各画素の第４電極４７２を電気的に接続する配線は、互いに交差しないように同一方向に延在して設けられてもよい。 Each of the third electrode 471 and the fourth electrode 472 may be provided independently for each pixel. The third electrode 471 of each pixel may be electrically connected to each other by a wiring provided on the second surface side extending in the extending direction of the third electrode 471. Similarly, the fourth electrode 472 of each pixel may be electrically connected to each other by a wiring provided on the second surface side extending in the extending direction of the fourth electrode 472. The wiring that electrically connects the third electrode 471 of each pixel and the wiring that electrically connects the fourth electrode 472 of each pixel may be provided so as to extend in the same direction so as not to intersect with each other.
　第１のバリエーションによれば、光検出装置４００Ａは、より単純な配線構造にて各画素の第３電極４７１又は第４電極４７２を電気的に接続することができる。したがって、光検出装置４００Ａは、製造工程をより簡素化することができる。 According to the first variation, the photodetector 400A can electrically connect the third electrode 471 or the fourth electrode 472 of each pixel with a simpler wiring structure. Therefore, the photodetector 400A can further simplify the manufacturing process.
　（第２のバリエーション）
　図４０は、第２のバリエーションに係る光検出装置４００Ｂの構成を説明する第２面側から見た平面図である。図４０では、光検出装置４００Ｂの構成のうち着目した構成についてのみ示す。 (Second variation)
FIG. 40 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400B according to the second variation. FIG. 40 shows only the configuration of interest among the configurations of the photodetector 400B.
　図４０に示すように、第３電極４７１及び電位制御領域４７３は、矩形形状の画素領域の一方の辺に沿って設けられ、第４電極４７２及びリセット領域４７４は、矩形形状の画素領域の一方の辺と対向する他方の辺に沿って設けられてもよい。 As shown in FIG. 40, the third electrode 471 and the potential control region 473 are provided along one side of the rectangular pixel region, and the fourth electrode 472 and the reset region 474 are one of the rectangular pixel regions. It may be provided along the other side facing the side of.
　第３電極４７１及び第４電極４７２の各々は、画素間で連続して設けられてもよい。具体的には、第３電極４７１は、電位制御領域４７３の延在方向に延在して設けられ、各画素の電位制御領域４７３と電気的に接続されていてもよい。また、第３電極４７１は、画素アレイの端部に設けられた配線によって、第３電極４７１の延在方向と直交する方向で互いに電気的に接続されてもよい。同様に、第４電極４７２は、リセット領域４７４の延在方向に延在して設けられ、各画素のリセット領域４７４と電気的に接続されていてもよい。また、第４電極４７２は、画素アレイの端部に設けられた配線によって、第４電極４７２の延在方向と直交する方向で互いに電気的に接続されてもよい。 Each of the third electrode 471 and the fourth electrode 472 may be continuously provided between the pixels. Specifically, the third electrode 471 may be provided so as to extend in the extending direction of the potential control region 473 and may be electrically connected to the potential control region 473 of each pixel. Further, the third electrode 471 may be electrically connected to each other in a direction orthogonal to the extending direction of the third electrode 471 by a wiring provided at the end of the pixel array. Similarly, the fourth electrode 472 may be provided so as to extend in the extending direction of the reset region 474 and may be electrically connected to the reset region 474 of each pixel. Further, the fourth electrode 472 may be electrically connected to each other in a direction orthogonal to the extending direction of the fourth electrode 472 by wiring provided at the end of the pixel array.
　第２のバリエーションによれば、光検出装置４００Ｂは、配線間の容量がより小さくなる配線構造にて各画素の第３電極４７１又は第４電極４７２を電気的に接続することができる。したがって、光検出装置４００Ｂは、配線間容量に起因するノイズを低減することができる。 According to the second variation, the photodetector 400B can electrically connect the third electrode 471 or the fourth electrode 472 of each pixel with a wiring structure in which the capacitance between the wirings is smaller. Therefore, the photodetector 400B can reduce the noise caused by the capacitance between the wirings.
　（第３のバリエーション）
　図４１は、第３のバリエーションに係る光検出装置４００Ｃの構造を示す縦断面図である。 (Third variation)
FIG. 41 is a vertical cross-sectional view showing the structure of the photodetector 400C according to the third variation.
　図４１に示すように、第１領域４１０よりも半導体基板の内部側には、第２導電型の第５領域４８０が設けられてもよい。具体的には、第５領域４８０は、第１領域４１０よりも半導体基板の内部側に設けられ、第２領域４２０又は電位制御領域４７３よりも不純物濃度が低い第２導電型の領域（例えば、Ｐ－層）である。第５領域４８０は、第１領域４１０からの電子の流れを抑制することで、ＤＣＲ（Ｄａｒｋ　Ｃｏｕｎｔ　Ｒａｔｅ）を低減し、暗時ノイズを低減することができる。 As shown in FIG. 41, a second conductive type fifth region 480 may be provided on the inner side of the semiconductor substrate with respect to the first region 410. Specifically, the fifth region 480 is provided on the inner side of the semiconductor substrate with respect to the first region 410, and is a second conductive type region (for example,) having a lower impurity concentration than the second region 420 or the potential control region 473 (for example). P-layer). The fifth region 480 can reduce DCR (Dark Count Rate) and reduce dark noise by suppressing the flow of electrons from the first region 410.
　なお、第５領域４８０は、光検出装置４００Ｂにて入射光の検出が終了した際に、第３領域４３０の内部に残存する電荷が第１領域４１０から排出されることも抑制してしまう。しかしながら、光検出装置４００Ｃは、別途、第３領域４３０の内部に残存する電荷を外部に排出することが可能なリセット領域４７４及び第４電極４７２を備えるため、第５領域４８０を設けることによる電子排出性の低下の影響を回避することができる。 Note that the fifth region 480 also suppresses the electric charge remaining inside the third region 430 from being discharged from the first region 410 when the detection of the incident light is completed by the photodetector 400B. However, since the photodetector 400C separately includes a reset region 474 and a fourth electrode 472 capable of discharging the electric charge remaining inside the third region 430 to the outside, the electron by providing the fifth region 480 is provided. It is possible to avoid the influence of the decrease in discharge.
　第３のバリエーションによれば、光検出装置４００Ｃは、第３領域４３０からの電子の排出性を低下させることなく、ＤＣＲ（Ｄａｒｋ　Ｃｏｕｎｔ　Ｒａｔｅ）を低減し、暗時ノイズを低減することができる。 According to the third variation, the photodetector 400C can reduce DCR (Dark Count Rate) and reduce dark noise without lowering the emission of electrons from the third region 430.
　（第４のバリエーション）
　図４２は、第４のバリエーションに係る光検出装置４００Ｄの構成を説明する第２面側から見た平面図である。図４２では、光検出装置４００Ｄの構成のうち着目した構成についてのみ示す。図４３Ａは、図４２のＡ－ＡＡ切断面における光検出装置４００Ｄの構成を示す縦断面図であり、図４３Ｂは、図４２のＢ－ＢＢ切断面における光検出装置４００Ｄの構成を示す縦断面図である。 (Fourth variation)
FIG. 42 is a plan view seen from the second surface side for explaining the configuration of the photodetector 400D according to the fourth variation. FIG. 42 shows only the configuration of interest in the configuration of the photodetector 400D. 43A is a vertical cross-sectional view showing the configuration of the photodetector 400D on the AA cut surface of FIG. 42, and FIG. 43B is a vertical cross section showing the configuration of the photodetector 400D on the B-BB cut surface of FIG. 42. It is a figure.
　図４２に示すように、第４のバリエーションに係る光検出装置４００Ｄは、第２のバリエーションに係る光検出装置４００Ｂに対して、貫通電極４７５が設けられる点が異なる。 As shown in FIG. 42, the photodetector 400D according to the fourth variation is different from the photodetector 400B according to the second variation in that a through electrode 475 is provided.
　具体的には、図４３Ａに示すように、Ａ－ＡＡ切断面では、光検出装置４００Ｄの構成は、図３７を参照して説明した基本構造に係る光検出装置４００の構成と略同一である。一方、図４２及び図４３Ｂに示すように、矩形形状の画素領域の第３電極４７１、電位制御領域４７３、第４電極４７２、及びリセット領域４７４が設けられない辺には、貫通電極４７５が設けられる。貫通電極４７５は、画素分離層４５０の内部にて半導体基板を第２面から第１面まで貫通して設けられ、半導体基板の第１面側に設けられた第１電極４１１と電気的に接続する。これによれば、貫通電極４７５は、各画素の第１電極４１１を互いに電気的に接続する配線を半導体基板の第２面側に形成することを可能にする。貫通電極４７５は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 Specifically, as shown in FIG. 43A, the configuration of the photodetector 400D on the AA cut surface is substantially the same as the configuration of the photodetector 400 according to the basic structure described with reference to FIG. 37. .. On the other hand, as shown in FIGS. 42 and 43B, through electrodes 475 are provided on the sides where the third electrode 471, the potential control region 473, the fourth electrode 472, and the reset region 474 are not provided in the rectangular pixel region. Be done. The through electrode 475 is provided inside the pixel separation layer 450 so as to penetrate the semiconductor substrate from the second surface to the first surface, and is electrically connected to the first electrode 411 provided on the first surface side of the semiconductor substrate. To do. According to this, the through electrode 475 makes it possible to form a wiring for electrically connecting the first electrodes 411 of each pixel to each other on the second surface side of the semiconductor substrate. The through silicon via 475 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided.
　さらに、貫通電極４７５と電気的に接続し、各画素の第１電極４１１を電気的に接続する配線は、半導体基板の面内において、第３電極４７１及び第４電極４７２の延在方向と直交する方向に延在して設けられてもよい。第３電極４７１及び第４電極４７２は半導体基板の内部に設けられるため、貫通電極４７５と電気的に接続する配線は、第３電極４７１及び第４電極４７２と干渉することなく配置することができる。 Further, the wiring electrically connected to the through electrode 475 and electrically connected to the first electrode 411 of each pixel is orthogonal to the extending direction of the third electrode 471 and the fourth electrode 472 in the plane of the semiconductor substrate. It may be provided so as to extend in the direction of Since the third electrode 471 and the fourth electrode 472 are provided inside the semiconductor substrate, the wiring electrically connected to the through electrode 475 can be arranged without interfering with the third electrode 471 and the fourth electrode 472. ..
　第４のバリエーションによれば、光検出装置４００Ｄは、光の入射面である第１面側に形成される配線を削減することができるため、光の入射面の開口率を向上させることができる。 According to the fourth variation, the photodetector 400D can reduce the wiring formed on the first surface side which is the incident surface of the light, so that the aperture ratio of the incident surface of the light can be improved. ..
　＜３．第３の実施形態＞
　（基本構造）
　次に、図４４～図４６を参照して、本開示の第３の実施形態に係る光検出装置の基本構造について説明する。 <3. Third Embodiment>
(Basic structure)
Next, with reference to FIGS. 44 to 46, the basic structure of the photodetector according to the third embodiment of the present disclosure will be described.
　まず、図４４及び図４５を参照して、本実施形態に係る光検出装置の基本特性について説明する。本実施形態に係る光検出装置は、印加されるバイアスを逆バイアスから順バイアスに反転させた際に順方向電流が流れるまでの遅延時間を計測することによって、入射する光を検出する、いわゆるＤＰＤセンサである。図４４は、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後の電荷の移動を時系列で示す模式図である。図４５は、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した後のエネルギーバンド構造の変化を時系列で示すグラフ図である。 First, the basic characteristics of the photodetector according to the present embodiment will be described with reference to FIGS. 44 and 45. The photodetector according to the present embodiment detects incident light by measuring the delay time until a forward current flows when the applied bias is reversed from a reverse bias to a forward bias, that is, a so-called DPD. It is a sensor. FIG. 44 is a schematic diagram showing the movement of electric charges after reversing the bias applied to the photodetector from the reverse bias to the forward bias in chronological order. FIG. 45 is a graph showing changes in the energy band structure in time series after reversing the bias applied to the photodetector from the reverse bias to the forward bias.
　図４４及び図４５の（１）に示すように、光検出装置に印加されるバイアスを逆バイアスから順バイアスに反転した場合、光検出装置では、まず、カソード電極（第１電極）からＰ＋層（第２領域）の周囲のエネルギーバンド構造の落ち込み（ディップとも称される）に向かって電子ｅが流入する。 As shown in (1) of FIGS. 44 and 45, when the bias applied to the light detection device is reversed from the reverse bias to the forward bias, the light detection device first starts with the cathode electrode (first electrode) to the P + layer. Electrons e flow toward the dip (also called dip) of the energy band structure around (the second region).
　これにより、図４４及び図４５の（２）に示すように、Ｐ＋層（第２領域）の周囲のポテンシャル障壁が低下する（ディップの深さが減少する）ため、Ｐ＋層（第２領域）から流出する正孔ｈが増加する。 As a result, as shown in (2) of FIGS. 44 and 45, the potential barrier around the P + layer (second region) is lowered (the depth of the dip is reduced), so that the P + layer (second region) Hole h flowing out from is increased.
　さらに、図４４及び図４５の（３）に示すように、Ｐ＋層（第２領域）からの正孔ｈの流出によって、Ｎ＋層（第１領域）の周囲のポテンシャル障壁が低下するため、Ｎ＋層（第１領域）からＰ＋層（第２領域）の周囲への電子ｅの流れがさらに増加する。その後も、Ｐ＋層（第２領域）からの正孔ｈの流出、及びＮ＋層（第１領域）からの電子ｅの流出が増加することで、Ｎ＋層（第１領域）及びＰ＋層（第２領域）の周囲のポテンシャル障壁が互いに低下する。 Further, as shown in (3) of FIGS. 44 and 45, the outflow of holes h from the P + layer (second region) lowers the potential barrier around the N + layer (first region), so that N + The flow of electrons e from the layer (first region) to the periphery of the P + layer (second region) is further increased. After that, the outflow of holes h from the P + layer (second region) and the outflow of electrons e from the N + layer (first region) increase, so that the N + layer (first region) and the P + layer (first region) are increased. The potential barriers around the two regions) decrease with each other.
　その後、図４４及び図４５の（４）に示すように、Ｐ＋層（第２領域）及びＮ＋層（第１領域）の間のポテンシャル障壁が消失し、光検出装置は、カソード電極（第１電極）及びアノード電極（第２電極）の間に順方向電流が流れる定常状態に達する。 After that, as shown in (4) of FIGS. 44 and 45, the potential barrier between the P + layer (second region) and the N + layer (first region) disappeared, and the photodetector used the cathode electrode (first region). A steady state is reached in which a forward current flows between the electrode) and the anode electrode (second electrode).
　本実施形態に係る光検出装置では、逆バイアスから順バイアスに反転してから上記の挙動によって定常状態に達するまでの時間が入射光の強度によって変化する。これは、入射光の光電変換にて生じた電子がカソード電極（第１電極）からＰ＋層（第２領域）の周囲のディップへの電子ｅの流入を加速させるためである。したがって、本実施形態に係る光検出装置は、印加バイアスを逆バイアスから順バイアスに反転させた際に、順方向電流が流れるまでの遅延時間を計測することによって、入射する光を検出することができる。 In the photodetector according to the present embodiment, the time from inversion from reverse bias to forward bias to reaching a steady state by the above behavior changes depending on the intensity of incident light. This is because the electrons generated by the photoelectric conversion of the incident light accelerate the inflow of the electrons e from the cathode electrode (first electrode) to the dip around the P + layer (second region). Therefore, the photodetector according to the present embodiment can detect incident light by measuring the delay time until the forward current flows when the applied bias is reversed from the reverse bias to the forward bias. it can.
　続いて、図４６を参照して、本開示の第３の実施形態に係る光検出装置の基本構造について説明する。図４６は、本実施形態に係る光検出装置５００の基本構造を示す縦断面図である。 Subsequently, with reference to FIG. 46, the basic structure of the photodetector according to the third embodiment of the present disclosure will be described. FIG. 46 is a vertical cross-sectional view showing the basic structure of the photodetector 500 according to the present embodiment.
　図４６に示すように、光検出装置５００は、第１領域５１０と、第２領域５２０と、第３領域５３０と、第１電極５１１と、第２電極５２１と、第４領域５２５と、絶縁層５７０とを備える。 As shown in FIG. 46, the photodetector 500 is insulated from the first region 510, the second region 520, the third region 530, the first electrode 511, the second electrode 521, and the fourth region 525. It includes a layer 570.
　第１領域５１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第１領域５１０は、例えば、半導体基板の第１面側に全面に広がって設けられてもよい。 The first region 510 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The first region 510 may be provided, for example, on the first surface side of the semiconductor substrate so as to spread over the entire surface.
　第２領域５２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第２領域５２０は、例えば、半導体基板の第２面側に島状に設けられてもよい。 The second region 520 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The second region 520 may be provided in an island shape on the second surface side of the semiconductor substrate, for example.
　第３領域５３０は、シリコン（Ｓｉ）などの半導体基板の第１領域５１０と第２領域５２０との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The third region 530 is a third conductive type region (for example, i-layer) provided between the first region 510 and the second region 520 of a semiconductor substrate such as silicon (Si).
　第１電極５１１は、半導体基板の第１面の上に設けられ、第１領域５１０と電気的に接続する。第１電極５１１は、例えば、カソード電極として機能する。例えば、第１電極５１１は、半導体基板の第１面に複数の画素に広がって設けられ、画素の各々の第１領域５１０に共通の電位を供給する共通電極であってもよい。 The first electrode 511 is provided on the first surface of the semiconductor substrate and is electrically connected to the first region 510. The first electrode 511 functions as, for example, a cathode electrode. For example, the first electrode 511 may be a common electrode that is spread over a plurality of pixels on the first surface of the semiconductor substrate and supplies a common potential to each first region 510 of the pixels.
　第２電極５２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域５２０と電気的に接続する。第２電極５２１は、例えば、アノード電極として機能する。 The second electrode 521 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 520. The second electrode 521 functions as, for example, an anode electrode.
　第１電極５１１、及び第２電極５２１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 The first electrode 511 and the second electrode 521 are, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), and polysilicon (poly-Si). , Or other conductive material.
　第４領域５２５は、第２領域５２０と接して半導体基板の深さ方向に設けられた第１導電型の領域（例えば、Ｎ層）である。具体的には、第４領域５２５は、第２領域５２０の直下の半導体基板の内部に設けられ、第１領域５１０よりも不純物濃度が低い第１導電型の領域であってもよい。 The fourth region 525 is a first conductive type region (for example, N layer) provided in contact with the second region 520 in the depth direction of the semiconductor substrate. Specifically, the fourth region 525 may be a first conductive type region provided inside the semiconductor substrate immediately below the second region 520 and having a lower impurity concentration than the first region 510.
　絶縁層５７０は、半導体基板の面内方向にて第２領域５２０を囲み、半導体基板の厚み方向にて第２領域５２０よりも深い領域まで設けられる。例えば、絶縁層５７０は、第２領域５２０の周囲を含む半導体基板の第２面の全面に広がって設けられてもよく、島状に設けられた第２領域５２０の周囲の領域のみに設けられてもよい。絶縁層５７０は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The insulating layer 570 surrounds the second region 520 in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520 in the thickness direction of the semiconductor substrate. For example, the insulating layer 570 may be provided over the entire second surface of the semiconductor substrate including the periphery of the second region 520, or may be provided only in the region around the second region 520 provided in an island shape. You may. The insulating layer 570 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　本実施形態に係る光検出装置５００は、例えば、入射するフォトンの数を計測するフォトンカウント用途に用いることができる。ここで、入射するフォトンの数を適切に計測するためには、図４４及び図４５を参照して説明した状態遷移において、光検出装置５００は、（１）に示した状態から（２）に示した状態へ１電子（すなわち、１光子）で遷移することが理想的である。このためには、光検出装置５００は、第２領域５２０に隣接して生じるポテンシャル障壁の容量を小さくすることで、ポテンシャル障壁に対する１電子当たりの変調力（すなわち、影響度）をより高めることが重要となる。 The photodetector 500 according to the present embodiment can be used, for example, for a photon counting application for measuring the number of incident photons. Here, in order to appropriately measure the number of incident photons, the photodetector 500 changes from the state shown in (1) to (2) in the state transition described with reference to FIGS. 44 and 45. Ideally, one electron (ie, one photon) transitions to the indicated state. For this purpose, the photodetector 500 can further increase the modulation force per electron (that is, the degree of influence) on the potential barrier by reducing the capacitance of the potential barrier generated adjacent to the second region 520. It becomes important.
　本実施形態に係る光検出装置５００は、第２領域５２０を島状の小面積にて形成することで、第２領域５２０にて生じる容量の大きさをより小さくすると共に、第２領域５２０の周囲を絶縁層５７０にて囲むことで、容量が生じる領域を第２領域５２０の下方に限定することができる。また、光検出装置５００は、第２導電型の第２領域５２０の下方に第１導電型の第４領域５２５を設けることで、内蔵電位によるポテンシャル障壁を発生させることができる。これによれば、光検出装置５００は、内蔵電位によるポテンシャル障壁を有し、かつ第２領域５２０に隣接した領域に生じるポテンシャル障壁の容量が小さくなるため、より少ない数の電子で動作することが可能となる。 In the photodetector 500 according to the present embodiment, the second region 520 is formed in a small island-shaped area, so that the size of the capacitance generated in the second region 520 is further reduced, and the second region 520 is formed. By surrounding the periphery with the insulating layer 570, the area where the capacitance is generated can be limited to the lower part of the second area 520. Further, the photodetector 500 can generate a potential barrier due to the built-in potential by providing the fourth region 525 of the first conductive type below the second region 520 of the second conductive type. According to this, the photodetector 500 has a potential barrier due to the built-in potential, and the capacity of the potential barrier generated in the region adjacent to the second region 520 becomes small, so that the photodetector 500 can operate with a smaller number of electrons. It will be possible.
　（バリエーション）
　続いて、図４７～図５３Ｂを参照して、本実施形態に係る光検出装置５００の構造のバリエーションについて説明する。 (variation)
Subsequently, with reference to FIGS. 47 to 53B, variations in the structure of the photodetector 500 according to the present embodiment will be described.
　（第１のバリエーション）
　図４７は、第１のバリエーションに係る光検出装置５００Ａの構造を示す縦断面図である。 (First variation)
FIG. 47 is a vertical cross-sectional view showing the structure of the photodetector 500A according to the first variation.
　図４７に示すように、第１領域５１０及び第１電極５１１は、半導体基板の第２面側（すなわち、第２領域５２０及び第２電極５２１が設けられた面側）に設けられてもよい。このような場合、同じ面側に設けられた第１領域５１０と第２領域５２０との間には、第２領域５２０の周囲を囲む絶縁層５７０の他に面内分離層５５２がさらに設けられてもよい。面内分離層５５２は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられる。面内分離層５５２は、第１領域５１０及び第２領域５２０の形成深さよりも深い領域まで形成されていてもよい。 As shown in FIG. 47, the first region 510 and the first electrode 511 may be provided on the second surface side of the semiconductor substrate (that is, the surface side where the second region 520 and the second electrode 521 are provided). .. In such a case, an in-plane separation layer 552 is further provided between the first region 510 and the second region 520 provided on the same surface side in addition to the insulating layer 570 surrounding the periphery of the second region 520. You may. The in-plane separation layer 552 is provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. The in-plane separation layer 552 may be formed to a region deeper than the formation depth of the first region 510 and the second region 520.
　第１のバリエーションによれば、光検出装置５００Ａは、第１領域５１０、第１電極５１１、第２領域５２０、及び第２電極５２１が半導体基板の同一の面側に設けられるため、製造工程をより単純化することができる。したがって、光検出装置５００Ａは、製造工程のプロセス難度を低下させることができる。 According to the first variation, in the photodetector 500A, the first region 510, the first electrode 511, the second region 520, and the second electrode 521 are provided on the same surface side of the semiconductor substrate, so that the manufacturing process can be performed. It can be simplified. Therefore, the photodetector 500A can reduce the process difficulty of the manufacturing process.
　（第２のバリエーション）
　図４８は、第２のバリエーションに係る光検出装置５００Ｂの構造を示す縦断面図である。 (Second variation)
FIG. 48 is a vertical cross-sectional view showing the structure of the photodetector 500B according to the second variation.
　図４８に示すように、光検出装置５００Ｂは、第１のバリエーションに係る光検出装置５００Ａに対して、絶縁層５７０が半導体基板の第２面の全面に広がって設けられる点が異なる。具体的には、半導体基板の第２面のうち第１領域５１０及び第２領域５２０が設けられた領域以外の領域には、絶縁層５７０が設けられてもよい。 As shown in FIG. 48, the photodetector 500B is different from the photodetector 500A according to the first variation in that the insulating layer 570 is provided so as to spread over the entire second surface of the semiconductor substrate. Specifically, the insulating layer 570 may be provided in a region other than the region where the first region 510 and the second region 520 are provided on the second surface of the semiconductor substrate.
　第２のバリエーションによれば、光検出装置５００Ｂは、第１領域５１０及び第２領域５２０による電荷の収集効率を向上させることができる。 According to the second variation, the photodetector 500B can improve the charge collection efficiency of the first region 510 and the second region 520.
　（第３のバリエーション）
　図４９は、第３のバリエーションに係る光検出装置５００Ｃの構造を示す縦断面図である。 (Third variation)
FIG. 49 is a vertical cross-sectional view showing the structure of the photodetector 500C according to the third variation.
　図４９に示すように、光検出装置５００Ｃは、第２のバリエーションに係る光検出装置５００Ｂに対して、第４領域５２５Ｃが絶縁層５７０の下方の半導体基板に広がって設けられる点が異なる。具体的には、第４領域５２５Ｃは、絶縁層５７０の形成深さよりも深い領域まで設けられ、絶縁層５７０の下方の半導体基板の内部まで広がって設けられてもよい。 As shown in FIG. 49, the photodetector 500C is different from the photodetector 500B according to the second variation in that the fourth region 525C is provided on the semiconductor substrate below the insulating layer 570. Specifically, the fourth region 525C may be provided to a region deeper than the formation depth of the insulating layer 570, and may be provided so as to extend to the inside of the semiconductor substrate below the insulating layer 570.
　第３のバリエーションによれば、光検出装置５００Ｃは、第１領域５１０及び第２領域５２０による電荷の収集効率を向上させることができる。 According to the third variation, the photodetector 500C can improve the charge collection efficiency of the first region 510 and the second region 520.
　（第４のバリエーション）
　図５０は、第４のバリエーションに係る光検出装置５００Ｄの構造を示す縦断面図である。 (Fourth variation)
FIG. 50 is a vertical cross-sectional view showing the structure of the photodetector 500D according to the fourth variation.
　図５０に示すように、光検出装置５００Ｄは、第３のバリエーションに係る光検出装置５００Ｃに対して、各領域の導電型の極性が入れ替わっている点が異なる。具体的には、第１領域５１０Ｄは、第２導電型の領域（例えば、Ｐ＋層）であり、半導体基板の第２面側に第２領域５２０Ｄと離隔して設けられる。第２領域５２０Ｄは、第１導電型の領域（例えば、Ｎ＋層）であり、半導体基板の第２面側に島状に設けられる。第４領域５２５Ｄは、第２導電型の領域（例えば、Ｐ層）であり、第２領域５２０Ｄと接して半導体基板の深さ方向に設けられる。例えば、第４領域５２５Ｄは、第２領域５２０Ｄの直下の半導体基板の内部にて絶縁層５７０の下方まで広がって設けられてもよい。 As shown in FIG. 50, the photodetector 500D differs from the photodetector 500C according to the third variation in that the polarities of the conductive type in each region are interchanged. Specifically, the first region 510D is a second conductive type region (for example, P + layer), and is provided on the second surface side of the semiconductor substrate at a distance from the second region 520D. The second region 520D is a first conductive type region (for example, N + layer), and is provided in an island shape on the second surface side of the semiconductor substrate. The fourth region 525D is a second conductive type region (for example, P layer), and is provided in contact with the second region 520D in the depth direction of the semiconductor substrate. For example, the fourth region 525D may be provided inside the semiconductor substrate directly below the second region 520D so as to extend below the insulating layer 570.
　第１電極５１１は、半導体基板の第２面の上に設けられ、第１領域５１０Ｄと電気的に接続する。第１電極５１１は、例えば、カソード電極として機能する。第２電極５２１は、半導体基板の第２面の上に設けられ、第２領域５２０Ｄと電気的に接続する。第２電極５２１は、例えば、アノード電極として機能する。絶縁層５７０は、半導体基板の面内方向にて第２領域５２０Ｄを囲み、半導体基板の厚み方向にて第２領域５２０Ｄよりも深い領域まで設けられる。 The first electrode 511 is provided on the second surface of the semiconductor substrate and is electrically connected to the first region 510D. The first electrode 511 functions as, for example, a cathode electrode. The second electrode 521 is provided on the second surface of the semiconductor substrate and is electrically connected to the second region 520D. The second electrode 521 functions as, for example, an anode electrode. The insulating layer 570 surrounds the second region 520D in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520D in the thickness direction of the semiconductor substrate.
　第４のバリエーションによれば、光検出装置５００Ｄは、印加されるバイアスが逆バイアスから順バイアスに反転された際に、電子ではなく正孔の移動を契機として動作することができる。 According to the fourth variation, the photodetector 500D can operate with the movement of holes instead of electrons when the applied bias is reversed from the reverse bias to the forward bias.
　（第５のバリエーション）
　図５１は、第５のバリエーションに係る光検出装置５００Ｅの構造を示す縦断面図である。 (Fifth variation)
FIG. 51 is a vertical cross-sectional view showing the structure of the photodetector 500E according to the fifth variation.
　図５１に示すように、光検出装置５００Ｅは、第３のバリエーションに係る光検出装置５００Ｃに対して、第１領域５１０が半導体基板の第１面側に設けられている点が異なる。 As shown in FIG. 51, the photodetector 500E is different from the photodetector 500C according to the third variation in that the first region 510 is provided on the first surface side of the semiconductor substrate.
　具体的には、第１領域５１０は、第１導電型の領域（例えば、Ｎ＋層）であり、半導体基板の第１面側に全面に広がって設けられる。第２領域５２０は、第２導電型の領域（例えば、Ｐ＋層）であり、半導体基板の第１面と反対側の第２面側に島状に設けられる。第４領域５２５は、第１導電型の領域（例えば、Ｎ層）であり、第２領域５２０と接して半導体基板の深さ方向に絶縁層５７０の下方にも広がって設けられる。 Specifically, the first region 510 is a first conductive type region (for example, N + layer), and is provided so as to spread over the entire surface on the first surface side of the semiconductor substrate. The second region 520 is a second conductive type region (for example, P + layer), and is provided in an island shape on the second surface side opposite to the first surface of the semiconductor substrate. The fourth region 525 is a first conductive type region (for example, N layer), and is provided in contact with the second region 520 and extends below the insulating layer 570 in the depth direction of the semiconductor substrate.
　第１電極５１１は、半導体基板の第１面の上に第１面絶縁層５５１を介して設けられ、第１面絶縁層５５１を貫通するビア５１２等を介して第１領域５１０と電気的に接続する。第２電極５２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域５２０と電気的に接続する。絶縁層５７０は、半導体基板の面内方向にて第２領域５２０を囲み、半導体基板の厚み方向にて第２領域５２０よりも深い領域まで設けられる。 The first electrode 511 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 551, and is electrically connected to the first region 510 via a via 512 or the like penetrating the first surface insulating layer 551. Connecting. The second electrode 521 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 520. The insulating layer 570 surrounds the second region 520 in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 520 in the thickness direction of the semiconductor substrate.
　第５のバリエーションによれば、光検出装置５００Ｅは、裏面（すなわち、第１面）照射型構造にて構成されるため、入射光に対して発生する電荷の数の割合（すなわち、量子効率）を向上させることができる。 According to the fifth variation, since the photodetector 500E is configured with a back surface (ie, first surface) irradiation type structure, the ratio of the number of charges generated to the incident light (that is, quantum efficiency). Can be improved.
　（第６のバリエーション）
　図５２は、第６のバリエーションに係る光検出装置５００Ｆの構造を示す縦断面図である。 (Sixth variation)
FIG. 52 is a vertical cross-sectional view showing the structure of the photodetector 500F according to the sixth variation.
　図５２に示すように、光検出装置５００Ｆは、第５のバリエーションに係る光検出装置５００Ｅに対して、画素間に画素分離層５５０がさらに設けられている点が異なる。 As shown in FIG. 52, the photodetector 500F is different from the photodetector 500E according to the fifth variation in that a pixel separation layer 550 is further provided between the pixels.
　具体的には、画素分離層５５０は、画素領域を囲みように半導体基板を厚み方向に貫通して設けられる。画素分離層５５０は、隣接する画素同士を電気的に離隔することで、隣接する画素間でのクロストークを抑制することができる。画素分離層５５０は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 Specifically, the pixel separation layer 550 is provided so as to penetrate the semiconductor substrate in the thickness direction so as to surround the pixel region. The pixel separation layer 550 can suppress crosstalk between adjacent pixels by electrically separating adjacent pixels from each other. The pixel separation layer 550 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　第６のバリエーションによれば、光検出装置５００Ｆは、隣接する画素間での物理的又は電気的な分離性が向上するため、画素間でのクロストークを抑制することができる。 According to the sixth variation, the photodetector 500F improves the physical or electrical separability between adjacent pixels, so that crosstalk between pixels can be suppressed.
　続いて、図５３Ａ及び図５３Ｂを参照して、第６のバリエーションに係る光検出装置５００Ｆの半導体基板の第２面における画素分離層５５０、絶縁層５７０、第２領域５２０、及び第２電極５２１の配置及び形状のバリエーションについて説明する。図５３Ａ及び図５３Ｂは、画素分離層５５０、絶縁層５７０、第２領域５２０、及び第２電極５２１の配置及び形状のバリエーションを説明する第２面側からの平面図である。 Subsequently, with reference to FIGS. 53A and 53B, the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521 on the second surface of the semiconductor substrate of the photodetector 500F according to the sixth variation The arrangement and shape variation of the above will be described. 53A and 53B are plan views from the second surface side for explaining variations in the arrangement and shape of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521.
　例えば、図５３Ａに示すように、第２領域５２０及び第２電極５２１は、画素分離層５５０によって矩形形状に確定された画素領域の略中央に矩形形状にて設けられてもよい。絶縁層５７０は、第２領域５２０及び第２電極５２１の周囲を角が丸くなった矩形形状にて囲んでいてもよい。なお、画素分離層５５０、絶縁層５７０、第２領域５２０、及び第２電極５２１の形状の重心は一致していてもよく、異なっていてもよい。 For example, as shown in FIG. 53A, the second region 520 and the second electrode 521 may be provided in a rectangular shape substantially in the center of the pixel region determined to be a rectangular shape by the pixel separation layer 550. The insulating layer 570 may surround the second region 520 and the second electrode 521 with a rectangular shape having rounded corners. The centers of gravity of the shapes of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521 may be the same or different.
　例えば、図５３Ｂに示すように、第２領域５２０及び第２電極５２１は、画素分離層５５０によって矩形形状に確定された画素領域の略中央に円形形状又は楕円形状にて設けられてもよい。絶縁層５７０は、第２領域５２０及び第２電極５２１の周囲を角が丸くなった矩形形状にて囲んでいてもよい。なお、画素分離層５５０、絶縁層５７０、第２領域５２０、及び第２電極５２１の形状の重心は一致していてもよく、異なっていてもよい。 For example, as shown in FIG. 53B, the second region 520 and the second electrode 521 may be provided in a circular shape or an elliptical shape substantially in the center of the pixel region determined to have a rectangular shape by the pixel separation layer 550. The insulating layer 570 may surround the second region 520 and the second electrode 521 with a rectangular shape having rounded corners. The centers of gravity of the shapes of the pixel separation layer 550, the insulating layer 570, the second region 520, and the second electrode 521 may be the same or different.
　図５３Ｂに示す平面形状によれば、第２領域５２０及び第２電極５２１は、電界集中がなくなり、電界を安定させることができるため、第２領域５２０に隣接する領域に生じるポテンシャル障壁の容量を低減することができる。また、このような平面形状によれば、第２領域５２０及び第２電極５２１は、より容易に微細化を進めることができる。 According to the planar shape shown in FIG. 53B, the second region 520 and the second electrode 521 eliminate the electric field concentration and can stabilize the electric field, so that the capacitance of the potential barrier generated in the region adjacent to the second region 520 is increased. It can be reduced. Further, according to such a planar shape, the second region 520 and the second electrode 521 can be miniaturized more easily.
　＜４．第４の実施形態＞
　（基本構造）
　次に、図５４～図５５Ｂを参照して、本開示の第４の実施形態に係る光検出装置の基本構造について説明する。図５４は、本実施形態に係る光検出装置６００の基本構造を示す縦断面図である。図５５Ａ及び図５５Ｂは、本実施形態に係る光検出装置６００のエネルギーバンド構造を示すグラフ図である。 <4. Fourth Embodiment>
(Basic structure)
Next, the basic structure of the photodetector according to the fourth embodiment of the present disclosure will be described with reference to FIGS. 54 to 55B. FIG. 54 is a vertical cross-sectional view showing the basic structure of the photodetector 600 according to the present embodiment. 55A and 55B are graphs showing the energy band structure of the photodetector 600 according to the present embodiment.
　図５４に示すように、光検出装置６００は、例えば、第１領域６１０と、第２領域６２０と、第３領域６３０と、第４領域６２５と、第５領域６１５と、第１電極６１１と、ビア６１２と、第１面絶縁層６５１と、画素分離層６５０と、第２電極６２１とを備える。 As shown in FIG. 54, the photodetector 600 includes, for example, a first region 610, a second region 620, a third region 630, a fourth region 625, a fifth region 615, and a first electrode 611. , The via 612, the first surface insulating layer 651, the pixel separation layer 650, and the second electrode 621 are provided.
　第１領域６１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域６２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第４領域６２５は、第２領域６２０よりも半導体基板の内部側に、第２領域６２０と接して設けられた第１導電型の領域（例えば、Ｎ＋層）である。第５領域６１５は、第１領域６１０よりも半導体基板の内部側に、第１領域６１０と接して設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域６３０は、半導体基板の第４領域６２５と第５領域６１５との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 610 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 620 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The fourth region 625 is a first conductive type region (for example, N + layer) provided in contact with the second region 620 on the inner side of the semiconductor substrate with respect to the second region 620. The fifth region 615 is a second conductive type region (for example, P + layer) provided in contact with the first region 610 on the inner side of the semiconductor substrate with respect to the first region 610. The third region 630 is a third conductive type region (for example, layer i) provided between the fourth region 625 and the fifth region 615 of the semiconductor substrate.
　すなわち、光検出装置６００は、第１領域６１０、第２領域６２０、第３領域６３０、第４領域６２５、及び第５領域６１５によって形成されたＰＮ／ｉ／ＰＮダイオードである。 That is, the photodetector 600 is a PN / i / PN diode formed by the first region 610, the second region 620, the third region 630, the fourth region 625, and the fifth region 615.
　第１電極６１１は、半導体基板の第１面の上に第１面絶縁層６５１を介して設けられ、第１面絶縁層６５１を貫通するビア６１２等を介して第１領域６１０と電気的に接続する。第１電極６１１は、例えば、カソード電極として機能する。第１電極６１１は、例えば、画素同士の境界に沿って設けられた画素分離層６５０を跨いで延在し、画素ごとに設けられたビア６１２にて各画素の第１領域６１０と電気的に接続する。すなわち、第１電極６１１は、各画素の第１領域６１０に共通の電位を供給する共通電極である。 The first electrode 611 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 651, and is electrically connected to the first region 610 via a via 612 or the like penetrating the first surface insulating layer 651. Connecting. The first electrode 611 functions as, for example, a cathode electrode. For example, the first electrode 611 extends across the pixel separation layer 650 provided along the boundary between pixels, and is electrically connected to the first region 610 of each pixel by a via 612 provided for each pixel. Connecting. That is, the first electrode 611 is a common electrode that supplies a common potential to the first region 610 of each pixel.
　画素分離層６５０は、半導体基板を厚み方向に貫通して設けられ、半導体基板の面内方向に複数設けられた画素の各々を互いに電気的に離隔する。画素分離層６５０は、例えば、半導体基板の面内方向に行列状に配列された各画素の境界に沿って格子状に設けられてもよい。 The pixel separation layer 650 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other. The pixel separation layer 650 may be provided, for example, in a grid pattern along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
　第２電極６２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域６２０と電気的に接続する。第２電極６２１は、例えば、アノード電極として機能する。 The second electrode 621 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 620. The second electrode 621 functions as, for example, an anode electrode.
　第１電極６１１、ビア６１２、及び第２電極６２１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。第１面絶縁層６５１、及び画素分離層６５０は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 611, the via 612, and the second electrode 621 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), and polysilicon (poly). -Si) or other conductive material may be provided. The first surface insulating layer 651 and the pixel separation layer 650 are provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. May be good.
　例えば、ＰＩＮダイオードを含む比較例に係る光検出装置では、印加バイアスを逆バイアスから順バイアスに反転させた直後に、光子が到達しなくとも順電流が発生してしまうことがあり得る。これは、印加バイアスを逆バイアスから順バイアスに反転させた際に生じるカソード電極側のポテンシャル障壁の高さによっては、ポテンシャル障壁を越えてカソード電極から容易に拡散電流が流れてしまうためである。これにより、アノード電極側のエネルギーバンド構造の落ち込み（ディップとも称される）が浅くなってしまうため、比較例に係る光検出装置では、光子が到達しなくとも順電流が発生してしまうことがあり得る。 For example, in the photodetector according to the comparative example including the PIN diode, a forward current may be generated even if the photon does not reach immediately after the applied bias is inverted from the reverse bias to the forward bias. This is because a diffusion current easily flows from the cathode electrode beyond the potential barrier depending on the height of the potential barrier on the cathode electrode side that occurs when the applied bias is inverted from the reverse bias to the forward bias. As a result, the dip (also called a dip) of the energy band structure on the anode electrode side becomes shallow, so that in the photodetector according to the comparative example, a forward current may be generated even if the photons do not reach. possible.
　本実施形態に係る光検出装置６００は、ＰＮ／ｉ／ＰＮダイオードを含む。そのため、図５５Ａに示すように、光検出装置６００は、第１領域６１０及び第５領域６１５のＰＮ接合による内蔵電位によって、カソード電極である第１電極６１１側にエネルギーバンドのポテンシャル障壁を定常的に形成することができる。これによれば、光検出装置６００は、拡散電流による電子の移動を抑制することができるため、光子の入射がない場合に順電流が発生してしまうことを抑制することができる。したがって、本実施形態に係る光検出装置６００は、偽信号の発生を抑制することが可能である。 The photodetector 600 according to this embodiment includes a PN / i / PN diode. Therefore, as shown in FIG. 55A, the photodetector 600 constantly sets a potential barrier of an energy band on the first electrode 611 side, which is a cathode electrode, by the built-in potential of the PN junction of the first region 610 and the fifth region 615. Can be formed into. According to this, since the photodetector 600 can suppress the movement of electrons due to the diffusion current, it is possible to suppress the generation of a forward current when there is no incident of photons. Therefore, the photodetector 600 according to the present embodiment can suppress the generation of false signals.
　このような光検出装置６００は、例えば、以下のように動作することができる。 Such a photodetector 600 can operate as follows, for example.
　具体的には、図５５Ｂに示すように、まず、光検出装置６００への光子の入射によって光電子が発生し、発生した光電子がエネルギーバンド構造のディップを埋めることで、エネルギーバンド構造のディップが浅くなる（Ｓ１）。これにより、アノード電極である第２電極６２１からカソード電極である第１電極６１１に正孔電流が流れるため、第１電極６１１側に内蔵電位によって形成されたエネルギーバンドのポテンシャル障壁が消失する（Ｓ２）。よって、カソード電極である第１電極６１１からアノード電極である第２電極６２１へ順電流が流れることができる（Ｓ３）。 Specifically, as shown in FIG. 55B, first, photoelectrons are generated by the incident of photons on the light detection device 600, and the generated photoelectrons fill the dip of the energy band structure, so that the dip of the energy band structure is shallow. Becomes (S1). As a result, the hole current flows from the second electrode 621, which is the anode electrode, to the first electrode 611, which is the cathode electrode, so that the potential barrier of the energy band formed by the built-in potential on the first electrode 611 side disappears (S2). ). Therefore, a forward current can flow from the first electrode 611, which is the cathode electrode, to the second electrode 621, which is the anode electrode (S3).
　（バリエーション）
　続いて、図５６Ａ～図６９を参照して、本実施形態に係る光検出装置６００の構造のバリエーションについて説明する。 (variation)
Subsequently, with reference to FIGS. 56A to 69, variations in the structure of the photodetector 600 according to the present embodiment will be described.
　（第１のバリエーション）
　図５６Ａは、第１のバリエーションに係る光検出装置６００Ａの構造を示す縦断面図である。図５６Ｂは、第１のバリエーションに係る光検出装置６００Ａの構造を示す第２面側から見た平面図である。 (First variation)
FIG. 56A is a vertical cross-sectional view showing the structure of the photodetector 600A according to the first variation. FIG. 56B is a plan view of the photodetector 600A according to the first variation as viewed from the second surface side.
　図５６Ａ及び図５６Ｂに示すように、第２領域６２０は、例えば、画素分離層６５０にて画定された領域の略全域に広がって設けられてもよい。同様に、第１領域６１０、第４領域６２５、及び第５領域６１５は、画素分離層６５０にて画定された領域の略全域に広がって設けられてもよい（図示せず）。一方、第２電極６２１は、例えば、画素分離層６５０にて画定された領域の略中央に島状に設けられてもよい。 As shown in FIGS. 56A and 56B, the second region 620 may be provided so as to extend over substantially the entire region defined by the pixel separation layer 650, for example. Similarly, the first region 610, the fourth region 625, and the fifth region 615 may be provided so as to extend over substantially the entire region defined by the pixel separation layer 650 (not shown). On the other hand, the second electrode 621 may be provided in an island shape at substantially the center of the region defined by the pixel separation layer 650, for example.
　第１のバリエーションによれば、光検出装置６００Ａは、半導体基板の厚み方向に第１領域６１０、第２領域６２０、第４領域６２５、及び第５領域６１５を配置することで、占有面積をより小さくすることができる。また、光検出装置６００Ａは、画素の全周に画素分離層６５０を設けることで、画素間のクロストークを抑制することができる。 According to the first variation, the photodetector 600A increases the occupied area by arranging the first region 610, the second region 620, the fourth region 625, and the fifth region 615 in the thickness direction of the semiconductor substrate. It can be made smaller. Further, the photodetector 600A can suppress crosstalk between pixels by providing the pixel separation layer 650 on the entire circumference of the pixels.
　（第２のバリエーション）
　図５７Ａは、第２のバリエーションに係る光検出装置６００Ｂの構造を示す縦断面図である。図５７Ｂは、第２のバリエーションに係る光検出装置６００Ｂの構造を示す第２面側から見た平面図である。 (Second variation)
FIG. 57A is a vertical cross-sectional view showing the structure of the photodetector 600B according to the second variation. FIG. 57B is a plan view of the photodetector 600B according to the second variation as viewed from the second surface side.
　図５７Ａ及び図５７Ｂに示すように、画素分離層６５０の半導体基板の第２面側には、第４領域６２５の電位を制御可能な制御電極６６１が設けられてもよい。制御電極６６１は、第４領域６２５の電位を制御することで、第２電極６２１側に形成されるエネルギーバンド構造のディップの深さ、及び該ディップを埋めるために必要な電荷量を制御することができる。 As shown in FIGS. 57A and 57B, a control electrode 661 capable of controlling the potential of the fourth region 625 may be provided on the second surface side of the semiconductor substrate of the pixel separation layer 650. The control electrode 661 controls the potential of the fourth region 625 to control the depth of the dip of the energy band structure formed on the second electrode 621 side and the amount of electric charge required to fill the dip. Can be done.
　具体的には、制御電極６６１は、半導体基板の第２面側から半導体基板の厚み方向に延在して設けられ、第４領域６２５と電気的に接続してもよい。例えば、制御電極６６１は、側面に側壁絶縁層６６２を備え、画素分離層６５０よりも大きな幅にて第４領域６２５まで延在して設けられることで、第４領域６２５と電気的に接続してもよい。制御電極６６１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。側壁絶縁層６６２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 Specifically, the control electrode 661 may be provided extending from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate and may be electrically connected to the fourth region 625. For example, the control electrode 661 is provided with a side wall insulating layer 662 on the side surface and is provided so as to extend to the fourth region 625 with a width larger than that of the pixel separation layer 650, so that the control electrode 661 is electrically connected to the fourth region 625. You may. The control electrode 661 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided. The side wall insulating layer 662 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
　第２のバリエーションによれば、光検出装置６００Ｂは、入射光の検出特性をより高い精度で制御することが可能である。 According to the second variation, the photodetector 600B can control the detection characteristics of the incident light with higher accuracy.
　（第３のバリエーション）
　図５８Ａは、第３のバリエーションに係る光検出装置６００Ｃの構造を示す縦断面図である。図５８Ｂは、第３のバリエーションに係る光検出装置６００Ｃの構造を示す第２面側から見た平面図である。 (Third variation)
FIG. 58A is a vertical cross-sectional view showing the structure of the photodetector 600C according to the third variation. FIG. 58B is a plan view of the photodetector 600C according to the third variation as viewed from the second surface side.
　図５８Ａ及び図５８Ｂに示すように、画素分離層６５０の半導体基板の第２面側には、第５領域６１５の電位を制御可能な制御電極６６１Ｃが設けられてもよい。制御電極６６１Ｃは、第５領域６１５の電位を制御することで、第１電極６１１側に形成されるエネルギーバンド構造のポテンシャル障壁の高さを制御することができる。 As shown in FIGS. 58A and 58B, a control electrode 661C capable of controlling the potential of the fifth region 615 may be provided on the second surface side of the semiconductor substrate of the pixel separation layer 650. The control electrode 661C can control the height of the potential barrier of the energy band structure formed on the first electrode 611 side by controlling the potential of the fifth region 615.
　具体的には、制御電極６６１Ｃは、半導体基板の第２面側から半導体基板の厚み方向に延在して設けられ、第５領域６１５と電気的に接続してもよい。例えば、制御電極６６１Ｃは、側面に側壁絶縁層６６２Ｃを備え、画素分離層６５０よりも大きな幅にて第５領域６１５まで延在して設けられることで、第５領域６１５と電気的に接続してもよい。制御電極６６１Ｃは、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。側壁絶縁層６６２Ｃは、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 Specifically, the control electrode 661C may be provided extending from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate and may be electrically connected to the fifth region 615. For example, the control electrode 661C is provided with a side wall insulating layer 662C on the side surface and is provided so as to extend to the fifth region 615 with a width larger than the pixel separation layer 650, so that the control electrode 661C is electrically connected to the fifth region 615. You may. The control electrode 661C is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided. The side wall insulating layer 662C may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material.
　第３のバリエーションによれば、光検出装置６００Ｃは、入射光の検出特性をより高い精度で制御することが可能である。 According to the third variation, the photodetector 600C can control the detection characteristics of the incident light with higher accuracy.
　（第４のバリエーション）
　図５９Ａは、第４のバリエーションに係る光検出装置６００Ｄの構造を示す縦断面図である。図５９Ｂは、第４のバリエーションに係る光検出装置６００Ｄの構造を示す第２面側から見た平面図である。 (Fourth variation)
FIG. 59A is a vertical cross-sectional view showing the structure of the photodetector 600D according to the fourth variation. FIG. 59B is a plan view of the photodetector 600D according to the fourth variation as viewed from the second surface side.
　図５９Ａ及び図５９Ｂに示すように、第２領域６２０Ｄは、半導体基板の第２面側に島状に設けられることで、第１領域６１０よりも体積が小さくなるように設けられてもよい。また、第４領域６２５Ｄは、第２領域６２０Ｄの側面及び底面を覆うように設けられてもよい。すなわち、光検出装置６００Ｄは、第２領域６２０Ｄ及び第４領域６２５Ｄによる第２電極６２１側のＰＮ接合の面積が、第１領域６１０及び第５領域６１５による第１電極６１１側のＰＮ接合の面積よりも小さくなるように設けられてもよい。 As shown in FIGS. 59A and 59B, the second region 620D may be provided so as to have a smaller volume than the first region 610 by being provided in an island shape on the second surface side of the semiconductor substrate. Further, the fourth region 625D may be provided so as to cover the side surface and the bottom surface of the second region 620D. That is, in the photodetector 600D, the area of the PN junction on the second electrode 621 side by the second region 620D and the fourth region 625D is the area of the PN junction on the first electrode 611 side by the first region 610 and the fifth region 615. It may be provided so as to be smaller than.
　これによれば、光検出装置６００Ｄは、第２電極６２１側の第２領域６２０Ｄに隣接する領域に生じる容量を小さくすることで、第２電極６２１側に形成されるエネルギーバンド構造のディップを埋めるために必要な電荷量を制御することができる。したがって、光検出装置６００Ｄは、より少ない光電子の数で動作することが可能となる。 According to this, the photodetector 600D fills the dip of the energy band structure formed on the second electrode 621 side by reducing the capacitance generated in the region adjacent to the second region 620D on the second electrode 621 side. The amount of charge required for this can be controlled. Therefore, the photodetector 600D can operate with a smaller number of photoelectrons.
　第４のバリエーションによれば、光検出装置６００Ｄは、入射光の検出特性をより向上させることができる。 According to the fourth variation, the photodetector 600D can further improve the detection characteristics of incident light.
　（第５のバリエーション）
　図６０は、第５のバリエーションに係る光検出装置６００Ｅの構造を示す縦断面図である。 (Fifth variation)
FIG. 60 is a vertical cross-sectional view showing the structure of the photodetector 600E according to the fifth variation.
　図６０に示すように、光検出装置６００Ｅは、第４のバリエーションに係る光検出装置６００Ｄに対して、第４領域６２５Ｅに制御電極６６３がさらに電気的に接続されている点が異なる。例えば、制御電極６６３は、半導体基板の第２面の上に設けられ、第４領域６２５Ｅと電気的に接続されていてもよい。制御電極６６３は、第４領域６２５Ｅの電位を制御することで、第２電極６２１側に形成されるエネルギーバンド構造のディップの深さ、及び該ディップを埋めるために必要な電荷量を制御することができる。制御電極６６３は、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 As shown in FIG. 60, the photodetector 600E is different from the photodetector 600D according to the fourth variation in that the control electrode 663 is further electrically connected to the fourth region 625E. For example, the control electrode 663 may be provided on the second surface of the semiconductor substrate and electrically connected to the fourth region 625E. By controlling the potential of the fourth region 625E, the control electrode 663 controls the depth of the dip of the energy band structure formed on the second electrode 621 side and the amount of electric charge required to fill the dip. Can be done. The control electrode 663 is provided of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. You may.
　第５のバリエーションによれば、光検出装置６００Ｅは、入射光の検出特性をより高い精度で制御することが可能である。 According to the fifth variation, the photodetector 600E can control the detection characteristics of the incident light with higher accuracy.
　（第６のバリエーション）
　図６１Ａは、第６のバリエーションに係る光検出装置６００Ｆの構造を示す縦断面図である。図６１Ｂは、第６のバリエーションに係る光検出装置６００Ｆの構造を示す第２面側から見た平面図である。 (Sixth variation)
FIG. 61A is a vertical cross-sectional view showing the structure of the photodetector 600F according to the sixth variation. FIG. 61B is a plan view of the photodetector 600F according to the sixth variation as viewed from the second surface side.
　図６１Ａ及び図６１Ｂに示すように、光検出装置６００Ｆは、第４のバリエーションに係る光検出装置６００Ｄに対して、第４領域６２５Ｆの上に制御ゲート６６４がさらに設けられている点が異なる。制御ゲート６６４は、第２領域６２０Ｆの周囲を囲む平面形状にて、第４領域６２５Ｆの上にゲート絶縁膜６６５を介して設けられてもよい。制御ゲート６６４は、電圧の印加によって、第４領域６２５Ｆの電位を制御することで、第２電極６２１側に形成されるエネルギーバンド構造のディップの深さ、及び該ディップを埋めるために必要な電荷量を制御することができる。 As shown in FIGS. 61A and 61B, the photodetector 600F is different from the photodetector 600D according to the fourth variation in that a control gate 664 is further provided on the fourth region 625F. The control gate 664 may be provided on the fourth region 625F with a gate insulating film 665 in a planar shape surrounding the circumference of the second region 620F. The control gate 664 controls the potential of the fourth region 625F by applying a voltage, so that the depth of the dip of the energy band structure formed on the second electrode 621 side and the electric charge required to fill the dip. The amount can be controlled.
　制御ゲート６６４は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。ゲート絶縁膜６６５は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The control gate 664 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided. The gate insulating film 665 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　第６のバリエーションによれば、光検出装置６００Ｆは、入射光の検出特性をより高い精度で制御することが可能である。 According to the sixth variation, the photodetector 600F can control the detection characteristics of the incident light with higher accuracy.
　（第７のバリエーション）
　図６２Ａは、第７のバリエーションに係る光検出装置６００Ｇの構造を示す縦断面図である。図６２Ｂは、第７のバリエーションに係る光検出装置６００Ｇの構造を示す第２面側から見た平面図である。 (7th variation)
FIG. 62A is a vertical cross-sectional view showing the structure of the photodetector 600G according to the seventh variation. FIG. 62B is a plan view of the photodetector 600G according to the seventh variation as viewed from the second surface side.
　図６２Ａ及び図６２Ｂに示すように、光検出装置６００Ｇには、半導体基板の面内方向にて第２領域６２０Ｇ及び第４領域６２５Ｇを囲む絶縁層６７０がさらに設けられていてもよい。 As shown in FIGS. 62A and 62B, the photodetector 600G may be further provided with an insulating layer 670 surrounding the second region 620G and the fourth region 625G in the in-plane direction of the semiconductor substrate.
　具体的には、第２領域６２０Ｇ及び第４領域６２５Ｇは、画素分離層６５０にて画定された画素領域の略中央に島状に設けられ、第２領域６２０Ｇ及び第４領域６２５Ｇの周囲を覆うように絶縁層６７０が設けられていてもよい。絶縁層６７０は、半導体基板の面内方向にて第２領域６２０Ｇ及び第４領域６２５Ｇを囲み、半導体基板の厚み方向にて第２領域６２０Ｇよりも深い領域まで設けられる。絶縁層６７０は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 Specifically, the second region 620G and the fourth region 625G are provided in an island shape substantially in the center of the pixel region defined by the pixel separation layer 650, and cover the periphery of the second region 620G and the fourth region 625G. As described above, the insulating layer 670 may be provided. The insulating layer 670 surrounds the second region 620G and the fourth region 625G in the in-plane direction of the semiconductor substrate, and is provided up to a region deeper than the second region 620G in the thickness direction of the semiconductor substrate. The insulating layer 670 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　絶縁層６７０は、第２領域６２０Ｇを島状の小面積とすることで、第２領域６２０Ｇに生じる容量の大きさをより小さくすることができる。また、絶縁層６７０は、第２領域６２０Ｇの周囲を囲むことで、第２領域６２０Ｇにて容量が生じる領域を第２領域６２０Ｇの内部側の半導体基板に限定することができる。これによれば、絶縁層６７０は、第２領域６２０Ｇに生じる容量を小さくすることで、第２電極６２１側に形成されるエネルギーバンド構造のディップを埋めるために必要な電荷量を制御することができる。したがって、光検出装置６００Ｇは、より少ない光電子の数で動作することが可能となる。 By making the second region 620G an island-shaped small area in the insulating layer 670, the size of the capacitance generated in the second region 620G can be made smaller. Further, by surrounding the insulating layer 670 around the second region 620G, the region where the capacitance is generated in the second region 620G can be limited to the semiconductor substrate on the inner side of the second region 620G. According to this, the insulating layer 670 can control the amount of electric charge required to fill the dip of the energy band structure formed on the second electrode 621 side by reducing the capacitance generated in the second region 620G. it can. Therefore, the photodetector 600G can operate with a smaller number of photoelectrons.
　第７のバリエーションによれば、光検出装置６００Ｇは、入射光の検出特性をより向上させることができる。 According to the seventh variation, the photodetector 600G can further improve the detection characteristics of incident light.
　（第８のバリエーション）
　図６３Ａは、第８のバリエーションに係る光検出装置６００Ｈの構造を示す縦断面図である。図６３Ｂは、第８のバリエーションに係る光検出装置６００Ｈの構造を示す第１面側から見た平面図である。 (8th variation)
FIG. 63A is a vertical cross-sectional view showing the structure of the photodetector 600H according to the eighth variation. FIG. 63B is a plan view of the photodetector 600H according to the eighth variation as viewed from the first surface side.
　図６３Ａ及び図６３Ｂに示すように、光検出装置６００Ｈは、第１のバリエーションに係る光検出装置６００Ａに対して、ＰＮ／ｉ／ＰＮダイオードが半導体基板の厚み方向ではなく、半導体基板の面内方向に形成される点が異なる。また、光検出装置６００Ｈでは、第１電極６１１及び第２電極６２１は、半導体基板の第１面の上にそれぞれ設けられる。 As shown in FIGS. 63A and 63B, in the photodetector 600H, the PN / i / PN diode is not in the thickness direction of the semiconductor substrate but in the plane of the semiconductor substrate with respect to the photodetector 600A according to the first variation. The points formed in the direction are different. Further, in the photodetector 600H, the first electrode 611 and the second electrode 621 are provided on the first surface of the semiconductor substrate, respectively.
　具体的には、第１領域６１０Ｈは、矩形形状の画素領域を画定する画素分離層６５０の一方の辺に沿って、半導体基板の第１面側の一部領域に設けられる。第５領域６１５Ｈは、第１領域６１０Ｈの側面及び底面を覆うように、第１領域６１０Ｈを挟んで画素分離層６５０と反対側の領域に設けられる。第２領域６２０Ｈは、矩形形状の画素領域を画定する画素分離層６５０の一方の辺と対向する他方の辺に沿って、半導体基板の第１面側の一部領域に設けられる。第４領域６２５Ｈは、第２領域６２０Ｈの側面及び底面を覆うように、第２領域６２０Ｈを挟んで画素分離層６５０と反対側の領域に設けられる。第３領域６３０は、第５領域６１５Ｈと第４領域６２５Ｈとの間の領域に設けられる。第１電極６１１は、半導体基板の第１面に露出された第１領域６１０Ｈの上に設けられ、第２電極６２１は、半導体基板の第１面に露出された第２領域６２０Ｈの上に設けられる。 Specifically, the first region 610H is provided in a part of the region on the first surface side of the semiconductor substrate along one side of the pixel separation layer 650 that defines the rectangular pixel region. The fifth region 615H is provided in a region opposite to the pixel separation layer 650 with the first region 610H interposed therebetween so as to cover the side surface and the bottom surface of the first region 610H. The second region 620H is provided in a part of the region on the first surface side of the semiconductor substrate along the other side facing one side of the pixel separation layer 650 that defines the rectangular pixel region. The fourth region 625H is provided in a region opposite to the pixel separation layer 650 with the second region 620H interposed therebetween so as to cover the side surface and the bottom surface of the second region 620H. The third region 630 is provided in the region between the fifth region 615H and the fourth region 625H. The first electrode 611 is provided on the first region 610H exposed on the first surface of the semiconductor substrate, and the second electrode 621 is provided on the second region 620H exposed on the first surface of the semiconductor substrate. Be done.
　第８のバリエーションによれば、光検出装置６００Ｇは、第１電極６１１及び第２電極６２１を半導体基板の同一面に形成することができるため、電極の形成をより容易に行うことができる。 According to the eighth variation, the photodetector 600G can form the first electrode 611 and the second electrode 621 on the same surface of the semiconductor substrate, so that the electrodes can be formed more easily.
　（第９のバリエーション）
　図６４Ａは、第９のバリエーションに係る光検出装置６００Ｉの構造を示す縦断面図である。図６４Ｂは、第９のバリエーションに係る光検出装置６００Ｉの構造を示す第１面側から見た平面図である。 (9th variation)
FIG. 64A is a vertical cross-sectional view showing the structure of the photodetector 600I according to the ninth variation. FIG. 64B is a plan view of the photodetector 600I according to the ninth variation as viewed from the first surface side.
　図６４Ａ及び図６４Ｂに示すように、光検出装置６００Ｉは、第８のバリエーションに係る光検出装置６００Ｈに対して、第１領域６１０Ｉ、第５領域６１５Ｉ、第４領域６２５Ｉ、及び第２領域６２０Ｉが半導体基板の第１面から第１面と反対側の第２面まで延在して設けられる点が異なる。これによれば、第１領域６１０Ｉ及び第２領域６２０Ｉは、画素分離層６５０と第３領域６３０との界面を覆うことで、ピニング効果によって該界面での電荷の誘起を抑制することができる。 As shown in FIGS. 64A and 64B, the photodetector 600I has a first region 610I, a fifth region 615I, a fourth region 625I, and a second region 620I with respect to the photodetector 600H according to the eighth variation. Is different in that is provided extending from the first surface of the semiconductor substrate to the second surface opposite to the first surface. According to this, the first region 610I and the second region 620I cover the interface between the pixel separation layer 650 and the third region 630, so that the induction of electric charge at the interface can be suppressed by the pinning effect.
　第９のバリエーションによれば、光検出装置６００Ｉは、半導体基板と、画素分離層６５０との界面での電荷の誘起を抑制することができるため、ノイズをより低減することができる。 According to the ninth variation, the photodetector 600I can suppress the induction of electric charge at the interface between the semiconductor substrate and the pixel separation layer 650, so that noise can be further reduced.
　（第１０のバリエーション）
　図６５は、第１０のバリエーションに係る光検出装置６００Ｊの構造を示す縦断面図である。 (10th variation)
FIG. 65 is a vertical cross-sectional view showing the structure of the photodetector 600J according to the tenth variation.
　図６５に示すように、光検出装置６００Ｊは、第８のバリエーションに係る光検出装置６００Ｈに対して、第５領域６１５Ｊに第１制御電極６６３Ｊ－１がさらに電気的に接続され、かつ第４領域６２５Ｊに第２制御電極６６３Ｊ－２がさらに電気的に接続される点が異なる。 As shown in FIG. 65, in the photodetector 600J, the first control electrode 663J-1 is further electrically connected to the fifth region 615J with respect to the photodetector 600H according to the eighth variation, and the fourth The difference is that the second control electrode 663J-2 is further electrically connected to the region 625J.
　具体的には、第５領域６１５Ｊは、第１領域６１０Ｊの側面及び底面を覆うように設けられ、第１制御電極６６３Ｊ－１は、半導体基板の第１面に露出された第５領域６１５Ｊの上に設けられてもよい。また、第４領域６２５Ｊは、第２領域６２０Ｊの側面及び底面を覆うように設けられ、第２制御電極６６３Ｊ－２は、半導体基板の第１面に露出された第４領域６２５Ｊの上に設けられてもよい。第１制御電極６６３Ｊ－１、及び第２制御電極６６３Ｊ－２は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 Specifically, the fifth region 615J is provided so as to cover the side surface and the bottom surface of the first region 610J, and the first control electrode 663J-1 is the fifth region 615J exposed on the first surface of the semiconductor substrate. It may be provided on the top. Further, the fourth region 625J is provided so as to cover the side surface and the bottom surface of the second region 620J, and the second control electrode 663J-2 is provided on the fourth region 625J exposed on the first surface of the semiconductor substrate. May be done. The first control electrode 663J-1 and the second control electrode 663J-2 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or poly. It may be provided of silicon (poly-Si) or other conductive material.
　第１制御電極６６３Ｊ－１は、第５領域６１５Ｊの電位を制御することで、第１電極６１１側に形成されるポテンシャル障壁の高さを制御することができる。また、第２制御電極６６３Ｊ－２は、第４領域６２５Ｊの電位を制御することで、第２電極６２１側に形成されるエネルギーバンド構造のディップの深さ、及び該ディップを埋めるために必要な電荷量を制御することができる。 The first control electrode 663J-1 can control the height of the potential barrier formed on the first electrode 611 side by controlling the potential of the fifth region 615J. Further, the second control electrode 663J-2 is necessary for controlling the potential of the fourth region 625J to fill the dip depth of the energy band structure formed on the second electrode 621 side and the dip. The amount of charge can be controlled.
　第１０のバリエーションによれば、光検出装置６００Ｊは、入射光の検出特性をより高い精度で制御することが可能である。 According to the tenth variation, the photodetector 600J can control the detection characteristics of the incident light with higher accuracy.
　（第１１のバリエーション）
　図６６Ａは、第１１のバリエーションに係る光検出装置６００Ｋの構造を示す縦断面図である。図６６Ｂは、第１１のバリエーションに係る光検出装置６００Ｋの構造を示す第１面側から見た平面図である。 (11th variation)
FIG. 66A is a vertical cross-sectional view showing the structure of the photodetector 600K according to the eleventh variation. FIG. 66B is a plan view seen from the first surface side showing the structure of the photodetector 600K according to the eleventh variation.
　図６６Ａ及び図６６Ｂに示すように、光検出装置６００Ｋは、第８のバリエーションに係る光検出装置６００Ｈに対して、第５領域６１５Ｋの上に第１制御ゲート６６４Ｋ－１がさらに設けられ、かつ第４領域６２５Ｋの上に第２制御ゲート６６４Ｋ－２がさらに設けられる点が異なる。 As shown in FIGS. 66A and 66B, the photodetector 600K is provided with a first control gate 664K-1 further on the fifth region 615K with respect to the photodetector 600H according to the eighth variation. The difference is that the second control gate 664K-2 is further provided on the fourth region 625K.
　具体的には、第１制御ゲート６６４Ｋ－１は、第１領域６１０Ｋの側面及び底面を覆うように設けられた第５領域６１５Ｋの上にゲート絶縁膜６６５Ｋ－１を介して設けられてもよい。第２制御ゲート６６４Ｋ－２は、第２領域６２０Ｋの側面及び底面を覆うように設けられた第４領域６２５Ｋの上にゲート絶縁膜６６５Ｋ－２を介して設けられてもよい。 Specifically, the first control gate 664K-1 may be provided via the gate insulating film 665K-1 on the fifth region 615K provided so as to cover the side surface and the bottom surface of the first region 610K. .. The second control gate 664K-2 may be provided via the gate insulating film 665K-2 on the fourth region 625K provided so as to cover the side surface and the bottom surface of the second region 620K.
　第１制御ゲート６６４Ｋ－１、及び第２制御ゲート６６４Ｋ－２は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。ゲート絶縁膜６６５Ｋ－１、６６５Ｋ－２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first control gate 664K-1 and the second control gate 664K-2 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or poly. It may be provided of silicon (poly-Si) or other conductive material. The gate insulating films 665K-1 and 665K-2 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. ..
　第１制御ゲート６６４Ｋ－１は、電圧の印加によって第５領域６１５Ｋの電位を制御することで、第１電極６１１側に形成されるポテンシャル障壁の高さを制御することができる。また、第２制御ゲート６６４Ｋ－２は、電圧の印加によって第４領域６２５Ｋの電位を制御することで、第２電極６２１側に形成されるエネルギーバンド構造のディップの深さ、及び該ディップを埋めるために必要な電荷量を制御することができる。 The first control gate 664K-1 can control the height of the potential barrier formed on the first electrode 611 side by controlling the potential of the fifth region 615K by applying a voltage. Further, the second control gate 664K-2 fills the dip depth of the energy band structure formed on the second electrode 621 side and the dip by controlling the potential of the fourth region 625K by applying a voltage. The amount of charge required for this can be controlled.
　第１１のバリエーションによれば、光検出装置６００Ｋは、入射光の検出特性をより高い精度で制御することが可能である。 According to the eleventh variation, the photodetector 600K can control the detection characteristics of the incident light with higher accuracy.
　（第１２のバリエーション）
　図６７は、第１２のバリエーションに係る光検出装置６００Ｌの構造を示す縦断面図である。 (12th variation)
FIG. 67 is a vertical cross-sectional view showing the structure of the photodetector 600L according to the twelfth variation.
　図６７に示すように、光検出装置６００Ｌは、第１のバリエーションに係る光検出装置６００Ａに対して、第１領域６１０Ｌ、第５領域６１５Ｌ、第３領域６３０Ｌ、第４領域６２５Ｌ、及び第２領域６２０Ｌを含む半導体基板がシリコン以外の半導体にて形成される点が異なる。 As shown in FIG. 67, the photodetector 600L has a first region 610L, a fifth region 615L, a third region 630L, a fourth region 625L, and a second region with respect to the photodetector 600A according to the first variation. The difference is that the semiconductor substrate including the region 620L is formed of a semiconductor other than silicon.
　例えば、第１領域６１０Ｌ、第５領域６１５Ｌ、第３領域６３０Ｌ、第４領域６２５Ｌ、及び第２領域６２０Ｌを含む半導体基板は、シリコンゲルマニウム（ＳｉＧｅ）、又はＩＩＩ－Ｖ族化合物半導体などで形成されてもよい。 For example, the semiconductor substrate including the first region 610L, the fifth region 615L, the third region 630L, the fourth region 625L, and the second region 620L is formed of silicon germanium (SiGe), a group III-V compound semiconductor, or the like. You may.
　第１２のバリエーションによれば、光検出装置６００Ｌは、検出可能な光の波長帯域を制御することが可能である。なお、第１２のバリエーションは、上述した第１～第１１のバリエーション、及び後述する第１３、第１４のバリエーションのいずれかと組み合わせることも可能である。 According to the twelfth variation, the photodetector 600L can control the wavelength band of the detectable light. The twelfth variation can be combined with any of the first to eleventh variations described above and the thirteenth and fourteenth variations described later.
　（第１３のバリエーション）
　図６８は、第１３のバリエーションに係る光検出装置６００Ｍの構造を示す縦断面図である。 (13th variation)
FIG. 68 is a vertical cross-sectional view showing the structure of the photodetector 600M according to the thirteenth variation.
　図６８に示すように、画素分離層６５０の内部には金属層６８１がさらに設けられてもよい。金属層６８１は、遮光性を有するため、半導体基板の第１面に斜め方向から入射する光が隣接する画素に進入することを防止することができる。金属層６８１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、又はこれらの合金にて設けられてもよい。 As shown in FIG. 68, a metal layer 681 may be further provided inside the pixel separation layer 650. Since the metal layer 681 has a light-shielding property, it is possible to prevent light incident on the first surface of the semiconductor substrate from an oblique direction from entering adjacent pixels. The metal layer 681 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
　第１３のバリエーションによれば、光検出装置６００Ｍは、金属層６８１によって画素間での光の進入を防止することができるため、画素間のクロストークをより抑制することができる。なお、第１３のバリエーションは、上述した第１～第１２のバリエーション、及び後述する第１４のバリエーションのいずれかと組み合わせることも可能である。 According to the thirteenth variation, the photodetector 600M can prevent the intrusion of light between pixels by the metal layer 681, so that crosstalk between pixels can be further suppressed. The thirteenth variation can be combined with any of the first to twelfth variations described above and the fourteenth variation described later.
　（第１４のバリエーション）
　図６９は、第１４のバリエーションに係る光検出装置６００Ｎの構造を示す縦断面図である。 (14th variation)
FIG. 69 is a vertical cross-sectional view showing the structure of the photodetector 600N according to the fourteenth variation.
　図６９に示すように、光検出装置６００Ｎは、半導体基板の第２面側に層間絶縁膜（図示せず）を介して設けられた反射層６８２をさらに備えてもよい。具体的には、反射層６８２は、半導体基板の第１面に入射した後、第３領域６３０を透過して半導体基板の第２面側に入射する光を反射することができる。これによれば、反射層６８２は、第３領域６３０を含む半導体基板に入射光を閉じ込めることができるため、第３領域６３０における光電変換効率を向上させることができる。 As shown in FIG. 69, the photodetector 600N may further include a reflective layer 682 provided on the second surface side of the semiconductor substrate via an interlayer insulating film (not shown). Specifically, the reflective layer 682 can reflect the light incident on the second surface side of the semiconductor substrate after being incident on the first surface of the semiconductor substrate and then passing through the third region 630. According to this, since the reflective layer 682 can confine the incident light in the semiconductor substrate including the third region 630, the photoelectric conversion efficiency in the third region 630 can be improved.
　反射層６８２は、画素分離層６５０にて画定された画素領域の全面に広がって設けられてもよい。反射層６８２は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、又はこれらの合金にて設けられてもよい。 The reflection layer 682 may be provided so as to spread over the entire surface of the pixel region defined by the pixel separation layer 650. The reflective layer 682 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
　第１４のバリエーションによれば、光検出装置６００Ｎは、第３領域６３０での光電変換効率を向上させることができるため、入射光の検出感度を向上させることができる。なお、第１４のバリエーションは、上述した第１～第１３のバリエーションのいずれかと組み合わせることも可能である。 According to the fourteenth variation, the photodetector 600N can improve the photoelectric conversion efficiency in the third region 630, so that the detection sensitivity of the incident light can be improved. The 14th variation can be combined with any of the 1st to 13th variations described above.
　＜５．第５の実施形態＞
　続いて、図７０～図１０８を参照して、本開示の第５の実施形態に係る光検出装置について説明する。 <5. Fifth Embodiment>
Subsequently, the photodetector according to the fifth embodiment of the present disclosure will be described with reference to FIGS. 70 to 108.
　本実施形態に係る光検出装置では、シリコン等の半導体層と絶縁体層との界面に第２導電型不純物を低濃度で含む層（例えば、Ｐ層）、又は負の固定電荷若しくは帯電性を有する層が設けられる。 In the photodetector according to the present embodiment, a layer containing a second conductive impurity at a low concentration (for example, P layer) at the interface between the semiconductor layer such as silicon and the insulator layer, or a negative fixed charge or chargeability is applied. A layer to have is provided.
　これによれば、第２導電型不純物を含む層は、半導体層と絶縁体層との界面で生じる界面準位の電子を層中の正孔と再結合させることができるため、半導体層と絶縁体層との界面で生じた電子によって偽信号又は暗電流が発生することを抑制することができる。また、負の固定電荷又は帯電性を有する層は、負の電界によって層界面に正孔蓄積層（ホールアキュムレーション層）を形成することができるため、半導体層と絶縁体層との界面での電荷（電子）の発生を抑制することができる。さらに、負の固定電荷又は帯電性を有する層は、半導体層と絶縁体層との界面で生じた電荷（電子）を正孔蓄積層にて消滅させることができるため、半導体層と絶縁体層との界面で生じた電子によって偽信号又は暗電流が発生することを抑制することができる。 According to this, the layer containing the second conductive type impurity can rebond the electrons at the interface state generated at the interface between the semiconductor layer and the insulator layer with the holes in the layer, so that the layer is insulated from the semiconductor layer. It is possible to suppress the generation of false signals or dark currents due to electrons generated at the interface with the body layer. Further, since the layer having a negative fixed charge or chargeability can form a hole accumulation layer (hole accumulation layer) at the layer interface by a negative electric field, the charge at the interface between the semiconductor layer and the insulator layer The generation of (electrons) can be suppressed. Further, in the layer having a negative fixed charge or chargeability, the charge (electrons) generated at the interface between the semiconductor layer and the insulator layer can be extinguished by the hole storage layer, so that the semiconductor layer and the insulator layer can be eliminated. It is possible to suppress the generation of false signals or dark currents due to the electrons generated at the interface with.
　本実施形態に係る光検出装置では、半導体層と絶縁体層との界面に、上述したような界面で生じる電荷を吸収する層（以下では、ピニング層とも称する）が設けられることで、偽信号又は暗電流の発生をより抑制することができる。 In the photodetector according to the present embodiment, a false signal is provided by providing a layer (hereinafter, also referred to as a pinning layer) that absorbs charges generated at the interface as described above at the interface between the semiconductor layer and the insulator layer. Alternatively, the generation of dark current can be further suppressed.
　以下では、本実施形態に係る光検出装置について、第２導電型不純物を含む層をピニング層として用いた構造例を第１～第１２の構造例として説明し、負の固定電荷又は帯電性を有する層をピニング層として用いた構造例を第１３～第１８の構造例として説明する。 Hereinafter, the photodetector according to the present embodiment will be described as a first to twelfth structural example using a layer containing a second conductive impurity as a pinning layer, and a negative fixed charge or chargeability will be described. A structural example using the provided layer as a pinning layer will be described as 13th to 18th structural examples.
　（第１の構造例）
　図７０は、第１の構造例に係る光検出装置７００Ａの構造を示す縦断面図である。図７１Ａ及び図７１Ｂは、第１の構造例に係る光検出装置７００Ａの平面構造の一例を示す上面図である。図７０にて示す光検出装置７００Ａの断面構造は、図７１Ａ及び図７１ＢのＡ－ＡＡ切断面における断面構造に対応する。 (First structural example)
FIG. 70 is a vertical cross-sectional view showing the structure of the photodetector 700A according to the first structural example. 71A and 71B are top views showing an example of the planar structure of the photodetector 700A according to the first structural example. The cross-sectional structure of the photodetector 700A shown in FIG. 70 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 71A and 71B.
　図７０に示すように、光検出装置７００Ａは、例えば、第１領域７１０と、第２領域７２０と、第３領域７３０と、ピニング層７４１と、絶縁膜７４０と、制御ゲート７６１と、ゲート絶縁膜７６２とを備える。 As shown in FIG. 70, the photodetector 700A includes, for example, a first region 710, a second region 720, a third region 730, a pinning layer 741, an insulating film 740, a control gate 761, and gate insulation. It includes a film 762.
　第１領域７１０は、シリコン（Ｓｉ）などの半導体基板に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域７２０は、シリコン（Ｓｉ）などの半導体基板に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域７３０は、シリコン（Ｓｉ）などの半導体基板の第１領域７１０及び第２領域７２０を除いた領域に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 710 is a first conductive type region (for example, N + layer) provided on a semiconductor substrate such as silicon (Si). The second region 720 is a second conductive type region (for example, P + layer) provided on a semiconductor substrate such as silicon (Si). The third region 730 is a third conductive type region (for example, the i-layer) provided in a region excluding the first region 710 and the second region 720 of the semiconductor substrate such as silicon (Si).
　制御ゲート７６１は、半導体基板の上にゲート絶縁膜７６２を介して設けられるゲート電極である。制御ゲート７６１は、電圧印加によって第３領域７３０におけるポテンシャル障壁を制御するために設けられる。制御ゲート７６１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。ゲート絶縁膜７６２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The control gate 761 is a gate electrode provided on the semiconductor substrate via the gate insulating film 762. The control gate 761 is provided to control the potential barrier in the third region 730 by applying a voltage. The control gate 761 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided. The gate insulating film 762 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　制御ゲート７６１は、例えば、第２領域７２０の周囲に設けられる。例えば、図７１Ａに示すように、制御ゲート７６１は、第１領域７１０及び第２領域７２０の配列方向にて第２領域７２０の両側にそれぞれ設けられてもよい。または、図７１Ｂに示すように、制御ゲート７６１は、第２領域７２０の全周を囲むように設けられてもよい。 The control gate 761 is provided, for example, around the second region 720. For example, as shown in FIG. 71A, the control gates 761 may be provided on both sides of the second region 720 in the arrangement direction of the first region 710 and the second region 720, respectively. Alternatively, as shown in FIG. 71B, the control gate 761 may be provided so as to surround the entire circumference of the second region 720.
　ここで、第１領域７１０及び第２領域７２０の配列方向にて、第１領域７１０及び制御ゲート７６１の間の領域が光検出装置７００Ａにおける光吸収領域７３１となる。光検出装置７００Ａは、光吸収領域７３１に入射した光を検出することができる。 Here, in the arrangement direction of the first region 710 and the second region 720, the region between the first region 710 and the control gate 761 becomes the light absorption region 731 in the photodetector 700A. The photodetector 700A can detect the light incident on the light absorption region 731.
　第１領域７１０には、例えば、カソード電極として機能する第１電極（図示せず）が電気的に接続される。また、第２領域７２０には、例えば、アノード電極として機能する第２電極（図示せず）が電気的に接続される。 For example, a first electrode (not shown) that functions as a cathode electrode is electrically connected to the first region 710. Further, for example, a second electrode (not shown) that functions as an anode electrode is electrically connected to the second region 720.
　絶縁膜７４０は、シリコン（Ｓｉ）などの半導体基板の表面に設けられる。絶縁膜７４０は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁材料にて設けられる。絶縁膜７４０は、例えば、シリコン基板の表面に形成された自然酸化膜であってもよく、第３領域７３０を保護するために半導体基板の表面に別途設けられた保護層であってもよい。 The insulating film 740 is provided on the surface of a semiconductor substrate such as silicon (Si). The insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. The insulating film 740 may be, for example, a natural oxide film formed on the surface of the silicon substrate, or may be a protective layer separately provided on the surface of the semiconductor substrate to protect the third region 730.
　ピニング層７４１は、第２領域７２０よりも不純物濃度が低い第２導電型の領域（例えば、Ｐ層）であり、シリコン（Ｓｉ）などの半導体基板と絶縁膜７４０との界面に設けられる。なお、ピニング層７４１と、第１領域７１０又は第２領域７２０との距離は、光検出装置７００Ａの動作時の最大電界が０．５ＭｅＶ／ｃｍ未満となるように設定され得る。ピニング層７４１は、例えば、第１領域７１０及び制御ゲート７６１の間に設けられた光吸収領域７３１の半導体基板と絶縁膜７４０との界面に設けられてもよい。 The pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is provided at the interface between the semiconductor substrate such as silicon (Si) and the insulating film 740. The distance between the pinning layer 741 and the first region 710 or the second region 720 can be set so that the maximum electric field during operation of the photodetector 700A is less than 0.5 MeV / cm. The pinning layer 741 may be provided, for example, at the interface between the semiconductor substrate of the light absorption region 731 and the insulating film 740 provided between the first region 710 and the control gate 761.
　ピニング層７４１は、半導体基板と絶縁膜７４０との界面で生じる界面準位の電子をピニング層７４１中の正孔と再結合させることができる。したがって、ピニング層７４１は、半導体基板と絶縁膜７４０との界面で生じた電子が第３領域７３０の空乏層中に流れ込み、偽信号又は暗電流となることを抑制することができる。 The pinning layer 741 can recombine the electrons at the interface state generated at the interface between the semiconductor substrate and the insulating film 740 with the holes in the pinning layer 741. Therefore, the pinning layer 741 can prevent electrons generated at the interface between the semiconductor substrate and the insulating film 740 from flowing into the depletion layer of the third region 730 and forming a false signal or a dark current.
　第１の構造例によれば、光検出装置７００Ａは、偽信号又は暗電流の発生を抑制することができる。 According to the first structural example, the photodetector 700A can suppress the generation of false signals or dark currents.
　（第２の構造例）
　図７２は、第２の構造例に係る光検出装置７００Ｂの構造を示す縦断面図である。図７３Ａ及び図７３Ｂは、第２の構造例に係る光検出装置７００Ｂの平面構造の一例を示す上面図である。図７２にて示す光検出装置７００Ｂの断面構造は、図７３Ａ及び図７３ＢのＡ－ＡＡ切断面における断面構造に対応する。 (Second structural example)
FIG. 72 is a vertical cross-sectional view showing the structure of the photodetector 700B according to the second structural example. 73A and 73B are top views showing an example of the planar structure of the photodetector 700B according to the second structural example. The cross-sectional structure of the photodetector 700B shown in FIG. 72 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 73A and 73B.
　図７２、図７３Ａ及び図７３Ｂに示すように、光検出装置７００Ｂは、第１の構造例に係る光検出装置７００Ａに対して、ピニング層７４１が光吸収領域７３１だけでなく、半導体基板の全面に広がって設けられる点が異なる。具体的には、ピニング層７４１は、第１領域７１０、第２領域７２０、及び制御ゲート７６１が設けられた領域の周囲をさらに囲むように設けられてもよい。 As shown in FIGS. 72, 73A and 73B, in the photodetector 700B, the pinning layer 741 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate with respect to the photodetector 700A according to the first structural example. The difference is that it is spread out in. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 761 are provided.
　第２の構造例によれば、光検出装置７００Ｂは、半導体基板と絶縁膜７４０との界面で生じた電子にて偽信号又は暗電流が発生することをさらに抑制することができる。 According to the second structural example, the photodetector 700B can further suppress the generation of false signals or dark currents due to the electrons generated at the interface between the semiconductor substrate and the insulating film 740.
　（第３の構造例）
　図７４は、第３の構造例に係る光検出装置７００Ｃの構造を示す縦断面図である。図７５Ａ、図７５Ｂ、図７７Ａ、及び図７７Ｂは、第３領域７３０を含む半導体層の表面側においてピニング層７４１が形成される領域の一例を示す平面図である。図７６Ａ、図７６Ｂ、図７８Ａ、及び図７８Ｂは、第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面においてピニング層７４１が形成される領域の一例を示す平面図である。なお、図７４にて示す光検出装置７００Ｃの断面構造は、図７５Ａ～図７８ＢのＡ－ＡＡ切断面における断面構造に対応する。 (Third structural example)
FIG. 74 is a vertical cross-sectional view showing the structure of the photodetector 700C according to the third structural example. 75A, 75B, 77A, and 77B are plan views showing an example of a region in which the pinning layer 741 is formed on the surface side of the semiconductor layer including the third region 730. 76A, 76B, 78A, and 78B are plan views showing an example of a region in which the pinning layer 741 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782. The cross-sectional structure of the photodetector 700C shown in FIG. 74 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 75A to 78B.
　図７４に示すように、光検出装置７００Ｃは、例えば、第１領域７１０と、第２領域７２０と、第３領域７３０と、ピニング層７４１と、絶縁膜７４０と、制御ゲート７６３と、ゲート絶縁膜７６４と、埋め込み絶縁膜７８２と、支持基板７８１とを備える。 As shown in FIG. 74, the photodetector 700C includes, for example, a first region 710, a second region 720, a third region 730, a pinning layer 741, an insulating film 740, a control gate 763, and gate insulation. A film 764, an embedded insulating film 782, and a support substrate 781 are provided.
　支持基板７８１は、例えば、シリコン（Ｓｉ）基板などの半導体基板である。埋め込み絶縁膜７８２は、例えば、酸化シリコン（ＳｉＯｘ）で形成され、支持基板７８１の上に設けられる。また、埋め込み絶縁膜７８２の上には、シリコン（Ｓｉ）などで形成された半導体層が設けられる。 The support substrate 781 is, for example, a semiconductor substrate such as a silicon (Si) substrate. The embedded insulating film 782 is formed of, for example, silicon oxide (SiO x ) and is provided on the support substrate 781. Further, a semiconductor layer made of silicon (Si) or the like is provided on the embedded insulating film 782.
　すなわち、光検出装置７００Ｃが形成される半導体基板は、いわゆるＳＯＩ（Ｓｉｌｉｃｏｎ　Ｏｎ　Ｉｎｓｕｌａｔｏｒ）基板である。支持基板７８１は、ＳＯＩ基板の支持基板に対応し、埋め込み絶縁膜７８２は、ＳＯＩ基板のＢＯＸ（Ｂｕｒｉｅｄ　ＯＸｉｄｅ）層に対応し、埋め込み絶縁膜７８２の上の半導体層は、ＳＯＩ基板の活性層に対応する。 That is, the semiconductor substrate on which the photodetector 700C is formed is a so-called SOI (Silicon On Insulator) substrate. The support substrate 781 corresponds to the support substrate of the SOI substrate, the embedded insulating film 782 corresponds to the BOX (Buried OXide) layer of the SOI substrate, and the semiconductor layer on the embedded insulating film 782 corresponds to the active layer of the SOI substrate. Correspond.
　第１領域７１０は、埋め込み絶縁膜７８２の上の半導体層に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域７２０は、埋め込み絶縁膜７８２の上の半導体層に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域７３０は、第１領域７１０及び第２領域７２０の間の半導体層に設けられた第３導電型の領域（例えば、ｉ層）である。第１領域７１０及び第２領域７２０は、半導体層の厚み方向に延在して、半導体層の表面から埋め込み絶縁膜７８２に達するまで設けられてもよい。 The first region 710 is a first conductive type region (for example, N + layer) provided in the semiconductor layer on the embedded insulating film 782. The second region 720 is a second conductive type region (for example, P + layer) provided in the semiconductor layer on the embedded insulating film 782. The third region 730 is a third conductive type region (for example, the i-layer) provided in the semiconductor layer between the first region 710 and the second region 720. The first region 710 and the second region 720 may extend in the thickness direction of the semiconductor layer and may be provided from the surface of the semiconductor layer until the embedded insulating film 782 is reached.
　第１領域７１０には、例えば、カソード電極として機能する第１電極（図示せず）が電気的に接続される。また、第２領域７２０には、例えば、アノード電極として機能する第２電極（図示せず）が電気的に接続される。 For example, a first electrode (not shown) that functions as a cathode electrode is electrically connected to the first region 710. Further, for example, a second electrode (not shown) that functions as an anode electrode is electrically connected to the second region 720.
　制御ゲート７６３は、半導体層の上に形成されたゲート絶縁膜７６４に埋め込まれるように設けられる。制御ゲート７６３は、例えば、第１領域７１０又は第２領域７２０に隣接する領域に設けられてもよい。制御ゲート７６３は、電圧印加によって第３領域７３０におけるポテンシャル障壁を制御することができる。 The control gate 763 is provided so as to be embedded in the gate insulating film 764 formed on the semiconductor layer. The control gate 763 may be provided, for example, in a region adjacent to the first region 710 or the second region 720. The control gate 763 can control the potential barrier in the third region 730 by applying a voltage.
　制御ゲート７６３は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。ゲート絶縁膜７６４は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The control gate 763 is made of, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), polysilicon (poly-Si), or other conductive material. It may be provided. The gate insulating film 764 may be provided with an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material.
　例えば、図７５Ａ～図７６Ｂに示すように、第１領域７１０及び第２領域７２０は、半導体層の面内方向にてそれぞれ一方向に延在して設けられてもよい。制御ゲート７６３は、第１領域７１０及び第２領域７２０の間の領域に、第１領域７１０及び第２領域７２０の各々に隣接して複数設けられてもよい。図７５Ａ～図７６Ｂでは、第１領域７１０及び第２領域７２０の配列方向にて、複数設けられた制御ゲート７６３の間の領域が光検出装置７００Ｃにおける光吸収領域７３１となる。 For example, as shown in FIGS. 75A to 76B, the first region 710 and the second region 720 may be provided extending in one direction in the in-plane direction of the semiconductor layer, respectively. A plurality of control gates 763 may be provided in a region between the first region 710 and the second region 720 adjacent to each of the first region 710 and the second region 720. In FIGS. 75A to 76B, the region between the plurality of control gates 763 provided in the arrangement direction of the first region 710 and the second region 720 is the light absorption region 731 in the photodetector 700C.
　また、図７７Ａ～図７８Ｂに示すように、第１領域７１０及び第２領域７２０は、半導体層の面内方向にてそれぞれ一方向に延在して設けられてもよい。制御ゲート７６３は、第１領域７１０及び第２領域７２０の間の領域に、環状の矩形形状にて設けられてもよい。具体的には、制御ゲート７６３は、第１領域７１０及び第２領域７２０の各々に隣接する２辺と、該２辺を互いに連結する２辺とからなる環状の矩形形状にて設けられてもよい。図７７Ａ～図７８Ｂでは、環状の矩形形状の制御ゲート７６３の内側の領域が光検出装置７００Ｃにおける光吸収領域７３１となる。 Further, as shown in FIGS. 77A to 78B, the first region 710 and the second region 720 may be provided extending in one direction in the in-plane direction of the semiconductor layer, respectively. The control gate 763 may be provided in the region between the first region 710 and the second region 720 in an annular rectangular shape. Specifically, the control gate 763 may be provided in an annular rectangular shape composed of two sides adjacent to each of the first region 710 and the second region 720 and two sides connecting the two sides to each other. Good. In FIGS. 77A to 78B, the region inside the annular rectangular control gate 763 is the light absorption region 731 in the photodetector 700C.
　絶縁膜７４０は、第３領域７３０を含む半導体層の表面に設けられる。絶縁膜７４０は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁材料にて設けられる。絶縁膜７４０は、例えば、半導体層の表面に形成された自然酸化膜であってもよく、第３領域７３０を保護するために半導体層の表面に別途設けられた保護層であってもよい。 The insulating film 740 is provided on the surface of the semiconductor layer including the third region 730. The insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. The insulating film 740 may be, for example, a natural oxide film formed on the surface of the semiconductor layer, or may be a protective layer separately provided on the surface of the semiconductor layer in order to protect the third region 730.
　ピニング層７４１は、第２領域７２０よりも不純物濃度が低い第２導電型の領域（例えば、Ｐ層）であり、第３領域７３０を含む半導体層と絶縁膜７４０との界面、又は第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面の一方又は両方に設けられる。 The pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is an interface between the semiconductor layer including the third region 730 and the insulating film 740, or a third region. It is provided at one or both of the interfaces between the semiconductor layer including 730 and the embedded insulating film 782.
　ピニング層７４１は、第３領域７３０を含む半導体層と、絶縁膜７４０又は埋め込み絶縁膜７８２との界面で生じる界面準位の電子をピニング層７４１中の正孔と再結合させることができる。したがって、ピニング層７４１は、半導体層と、絶縁膜７４０又は埋め込み絶縁膜７８２との界面で生じた電子が第３領域７３０の空乏層中に流れ込み、偽信号又は暗電流となることを抑制することができる。 The pinning layer 741 can recombine the electrons at the interface state generated at the interface between the semiconductor layer including the third region 730 and the insulating film 740 or the embedded insulating film 782 with the holes in the pinning layer 741. Therefore, the pinning layer 741 suppresses that electrons generated at the interface between the semiconductor layer and the insulating film 740 or the embedded insulating film 782 flow into the depletion layer of the third region 730 and become a false signal or a dark current. Can be done.
　ここで、図７５Ａ及び図７７Ａに示すように、第３領域７３０を含む半導体層と、絶縁膜７４０との界面に設けられたピニング層７４１は、制御ゲート７６３の間又は内側の光吸収領域７３１に設けられてもよい。または、図７５Ｂ及び図７７Ｂに示すように、第３領域７３０を含む半導体層と、絶縁膜７４０との界面に設けられたピニング層７４１は、光吸収領域７３１だけでなく、半導体基板の全面に広がって設けられてもよい。具体的には、ピニング層７４１は、第１領域７１０、第２領域７２０、及び制御ゲート７６３が設けられた領域の周囲をさらに囲むように設けられてもよい。 Here, as shown in FIGS. 75A and 77A, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the insulating film 740 is formed in the light absorption region 731 between or inside the control gate 763. It may be provided in. Alternatively, as shown in FIGS. 75B and 77B, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the insulating film 740 is provided not only on the light absorption region 731 but also on the entire surface of the semiconductor substrate. It may be spread out. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 763 are provided.
　一方、図７６Ａ及び図７８Ａに示すように、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、第１領域７１０及び第２領域７２０の間の領域に設けられてもよい。または、図７６Ｂ及び図７８Ｂに示すように、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、光吸収領域７３１だけでなく、半導体基板の全面に広がって設けられてもよい。具体的には、ピニング層７４１は、第１領域７１０及び第２領域７２０が設けられた領域の周囲をさらに囲むように設けられてもよい。すなわち、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、制御ゲート７６３の下まで延在して設けられてもよい。 On the other hand, as shown in FIGS. 76A and 78A, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is located between the first region 710 and the second region 720. It may be provided in the area. Alternatively, as shown in FIGS. 76B and 78B, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate. It may be spread over and provided. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710 and the second region 720 are provided. That is, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 may extend to the bottom of the control gate 763.
　第３の構造例によれば、光検出装置７００Ｃは、形成された基板がＳＯＩ基板であっても、偽信号又は暗電流の発生を抑制することができる。 According to the third structural example, the photodetector 700C can suppress the generation of false signals or dark currents even if the formed substrate is an SOI substrate.
　（第４の構造例）
　図７９は、第４の構造例に係る光検出装置７００Ｄの構造を示す縦断面図である。図８０Ａ、図８０Ｂ、図８２Ａ、及び図８２Ｂは、電荷生成層７８３の表面側においてピニング層７４１が形成される領域の一例を示す平面図である。図８１Ａ、図８１Ｂ、図８３Ａ、及び図８３Ｂは、第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面においてピニング層７４１が形成される領域の一例を示す平面図である。なお、図７９にて示す光検出装置７００Ｄの断面構造は、図８０Ａ～図８３ＢのＡ－ＡＡ切断面における断面構造に対応する。 (Fourth structural example)
FIG. 79 is a vertical cross-sectional view showing the structure of the photodetector 700D according to the fourth structural example. 80A, 80B, 82A, and 82B are plan views showing an example of a region where the pinning layer 741 is formed on the surface side of the charge generation layer 783. 81A, 81B, 83A, and 83B are plan views showing an example of a region in which the pinning layer 741 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782. The cross-sectional structure of the photodetector 700D shown in FIG. 79 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 80A to 83B.
　図７９に示すように、光検出装置７００Ｄは、第３の構造例に係る光検出装置７００Ｃに対して、第３領域７３０を含む半導体層の上に電荷生成層７８３が設けられ、電荷生成層７８３の表面にピニング層７４１が形成される点が異なる。 As shown in FIG. 79, in the photodetector 700D, the charge generation layer 783 is provided on the semiconductor layer including the third region 730 with respect to the photodetector 700C according to the third structural example, and the charge generation layer 783 is provided. The difference is that the pinning layer 741 is formed on the surface of 783.
　電荷生成層７８３は、半導体材料にて形成され、半導体層の上の制御ゲート７６３の間又は内側の領域に設けられる。電荷生成層７８３は、入射光を光電変換することで電荷を生成することができる。例えば、電荷生成層７８３は、ゲルマニウム（Ｇｅ）、ヒ化ガリウム（ＧａＡｓ）、又はシリコンゲルマニウム（ＳｉＧｅ）のうちの１つ又はこれら混合物にて形成されてもよく、低濃度又は高濃度の導電型不純物をドーピングされたシリコンで形成されてもよい。 The charge generation layer 783 is formed of a semiconductor material and is provided in the region between or inside the control gates 763 on the semiconductor layer. The charge generation layer 783 can generate an electric charge by photoelectrically converting the incident light. For example, the charge generation layer 783 may be formed of one of germanium (Ge), gallium arsenide (GaAs), or silicon germanium (SiGe) or a mixture thereof, and is a low-concentration or high-concentration conductive type. It may be formed of silicon doped with impurities.
　これによれば、電荷生成層７８３は、例えば、第３領域７３０で光電変換されない波長帯域の光を光電変換することができる。また、電荷生成層７８３は、例えば、第３領域７３０と同様に入射光を光電変換することで、光検出装置７００Ｄの量子効率を向上させることができる。 According to this, the charge generation layer 783 can, for example, photoelectrically convert light in a wavelength band that is not photoelectrically converted in the third region 730. Further, the charge generation layer 783 can improve the quantum efficiency of the photodetector 700D by photoelectrically converting the incident light in the same manner as in the third region 730, for example.
　図８０Ａ～図８１Ｂに示すように、制御ゲート７６３は、同一方向に延在して設けられる第１領域７１０及び第２領域７２０の間の領域に第１領域７１０及び第２領域７２０の各々に隣接して複数設けられてもよい。図８０Ａ～図８１Ｂでは、第１領域７１０及び第２領域７２０の配列方向での制御ゲート７６３の各々の間の領域が光検出装置７００Ｄにおける光吸収領域７３１となる。 As shown in FIGS. 80A to 81B, the control gate 763 is provided in the region between the first region 710 and the second region 720 extending in the same direction in each of the first region 710 and the second region 720. A plurality of them may be provided adjacent to each other. In FIGS. 80A to 81B, the region between each of the control gates 763 in the arrangement direction of the first region 710 and the second region 720 is the light absorption region 731 in the photodetector 700D.
　図８２Ａ～図８３Ｂに示すように、制御ゲート７６３は、同一方向に延在して設けられる第１領域７１０及び第２領域７２０の間の領域に、環状の矩形形状にて設けられてもよい。具体的には、制御ゲート７６３は、第１領域７１０及び第２領域７２０の各々に隣接する２辺と、該２辺を互いに連結する２辺とからなる環状の矩形形状にて設けられてもよい。図８２Ａ～図８３Ｂでは、環状の矩形形状の制御ゲート７６３の内側の領域が光検出装置７００Ｄにおける光吸収領域７３１となる。 As shown in FIGS. 82A to 83B, the control gate 763 may be provided in an annular rectangular shape in a region between the first region 710 and the second region 720 extending in the same direction. .. Specifically, the control gate 763 may be provided in an annular rectangular shape composed of two sides adjacent to each of the first region 710 and the second region 720 and two sides connecting the two sides to each other. Good. In FIGS. 82A to 83B, the region inside the annular rectangular control gate 763 is the light absorption region 731 in the photodetector 700D.
　絶縁膜７４０は、電荷生成層７８３の表面に設けられる。絶縁膜７４０は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁材料にて設けられる。絶縁膜７４０は、例えば、電荷生成層７８３の表面に形成された自然酸化膜であってもよく、電荷生成層７８３を保護するために別途設けられた保護層であってもよい。 The insulating film 740 is provided on the surface of the charge generation layer 783. The insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. The insulating film 740 may be, for example, a natural oxide film formed on the surface of the charge generation layer 783, or may be a protective layer separately provided to protect the charge generation layer 783.
　ピニング層７４１は、第２領域７２０よりも不純物濃度が低い第２導電型の領域（例えば、Ｐ層）であり、電荷生成層７８３と絶縁膜７４０との界面、又は第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面の一方又は両方に設けられる。ピニング層７４１は、電荷生成層７８３と絶縁膜７４０との界面、又は第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面で生じた電荷が第３領域７３０の空乏層中に流れ込み、偽信号又は暗電流となることを抑制することができる。 The pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720, and is a semiconductor including the interface between the charge generation layer 783 and the insulating film 740 or the third region 730. It is provided on one or both of the interfaces between the layer and the embedded insulating film 782. In the pinning layer 741, the electric charge generated at the interface between the charge generation layer 783 and the insulating film 740 or the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 flows into the depletion layer of the third region 730. It is possible to suppress a false signal or a dark current.
　ここで、図８０Ａ及び図８２Ａに示すように、電荷生成層７８３と、絶縁膜７４０との界面に設けられたピニング層７４１は、制御ゲート７６３の間又は内側の光吸収領域７３１に設けられてもよい。または、図８０Ｂ及び図８２Ｂに示すように、電荷生成層７８３と、絶縁膜７４０との界面に設けられたピニング層７４１は、光吸収領域７３１だけでなく、半導体基板の全面に広がって設けられてもよい。具体的には、ピニング層７４１は、第１領域７１０、第２領域７２０、及び制御ゲート７６３が設けられた領域の周囲をさらに囲むように設けられてもよい。 Here, as shown in FIGS. 80A and 82A, the pinning layer 741 provided at the interface between the charge generation layer 783 and the insulating film 740 is provided in the light absorption region 731 between the control gates 763 or inside. May be good. Alternatively, as shown in FIGS. 80B and 82B, the pinning layer 741 provided at the interface between the charge generation layer 783 and the insulating film 740 is provided not only in the light absorption region 731 but also over the entire surface of the semiconductor substrate. You may. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710, the second region 720, and the control gate 763 are provided.
　一方、図８１Ａ及び図８３Ａに示すように、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、第１領域７１０及び第２領域７２０の間の平面領域に設けられてもよい。 On the other hand, as shown in FIGS. 81A and 83A, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is located between the first region 710 and the second region 720. It may be provided in a plane region.
　また、図８１Ｂ及び図８３Ｂに示すように、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、光吸収領域７３１だけでなく、半導体基板の全面に広がって設けられてもよい。具体的には、ピニング層７４１は、第１領域７１０及び第２領域７２０が設けられた領域の周囲をさらに囲むように設けられてもよい。すなわち、第３領域７３０を含む半導体層と、埋め込み絶縁膜７８２との界面に設けられたピニング層７４１は、制御ゲート７６３の下まで延在して設けられてもよい。 Further, as shown in FIGS. 81B and 83B, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 is not only the light absorption region 731 but also the entire surface of the semiconductor substrate. It may be spread over and provided. Specifically, the pinning layer 741 may be provided so as to further surround the region in which the first region 710 and the second region 720 are provided. That is, the pinning layer 741 provided at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 may extend to the bottom of the control gate 763.
　第４の構造例によれば、光検出装置７００Ｄは、入射光に対する光電変換特性を向上させることができる。 According to the fourth structural example, the photodetector 700D can improve the photoelectric conversion characteristic with respect to the incident light.
　（第５の構造例）
　図８４は、第５の構造例に係る光検出装置７００Ｅの構造を示す縦断面図である。 (Fifth structural example)
FIG. 84 is a vertical cross-sectional view showing the structure of the photodetector 700E according to the fifth structural example.
　図８４に示すように、光検出装置７００Ｅは、第３の構造例に係る光検出装置７００Ｃに対して、光検出装置７００Ｅが形成される基板がＳＯＩ基板ではなく、シリコン基板等の半導体基板である点が異なる。このような場合、ピニング層７４１は、第３領域７３０を含む半導体基板と絶縁膜７４０との界面に設けられてもよい。 As shown in FIG. 84, in the photodetector 700E, the substrate on which the photodetector 700E is formed is not an SOI substrate but a semiconductor substrate such as a silicon substrate with respect to the photodetector 700C according to the third structural example. There is a difference. In such a case, the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and the insulating film 740.
　第５の構造例によれば、光検出装置７００Ｅは、より安価な基板を用いることで、製造コストを低減することが可能である。 According to the fifth structural example, the photodetector 700E can reduce the manufacturing cost by using a cheaper substrate.
　（第６の構造例）
　図８５は、第６の構造例に係る光検出装置７００Ｆの構造を示す縦断面図である。 (Sixth structural example)
FIG. 85 is a vertical cross-sectional view showing the structure of the photodetector 700F according to the sixth structural example.
　図８５に示すように、光検出装置７００Ｆは、第３の構造例に係る光検出装置７００Ｃに対して、第３領域７３０を含む半導体層の上にモノリシック構造７８４が設けられ、モノリシック構造７８４の側面にピニング層７４１が形成される点が異なる。 As shown in FIG. 85, in the photodetector 700F, the monolithic structure 784 is provided on the semiconductor layer including the third region 730 with respect to the photodetector 700C according to the third structural example, and the monolithic structure 784 is provided. The difference is that the pinning layer 741 is formed on the side surface.
　モノリシック構造７８４は、１つの半導体基板を加工することで形成された構造であり、半導体層の上の制御ゲート７６３の間又は内側の領域に設けられる。モノリシック構造７８４は、入射光を光電変換する光吸収層であり、例えば、シリコン（Ｓｉ）、ゲルマニウム（Ｇｅ）、又は炭化シリコン（ＳｉＣ）などを含んでもよい。これによれば、光検出装置７００Ｆは、入射光に対する光電変換特性を向上させることができる。 The monolithic structure 784 is a structure formed by processing one semiconductor substrate, and is provided between or in the inner region of the control gate 763 on the semiconductor layer. The monolithic structure 784 is a light absorption layer that photoelectrically converts incident light, and may contain, for example, silicon (Si), germanium (Ge), silicon carbide (SiC), or the like. According to this, the photodetector 700F can improve the photoelectric conversion characteristic with respect to the incident light.
　ここで、モノリシック構造７８４の第３領域７３０との積層面と反対側の面には、コンタクト層７８５が設けられてもよい。コンタクト層７８５は、例えば、第２導電型の領域（例えば、Ｐ＋層）である。光検出装置７００Ｆは、コンタクト層７８５を介してモノリシック構造７８４に電圧を印加することで、モノリシック構造７８４の電位を制御することができる。 Here, the contact layer 785 may be provided on the surface of the monolithic structure 784 opposite to the laminated surface with the third region 730. The contact layer 785 is, for example, a second conductive type region (for example, a P + layer). The photodetector 700F can control the potential of the monolithic structure 784 by applying a voltage to the monolithic structure 784 via the contact layer 785.
　また、モノリシック構造７８４の側面には、絶縁膜７４０が設けられる。絶縁膜７４０は、例えば、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁材料にて設けられる。絶縁膜７４０は、例えば、モノリシック構造７８４の側面に形成された自然酸化膜であってもよく、モノリシック構造７８４を保護するために別途設けられた保護層であってもよい。 An insulating film 740 is provided on the side surface of the monolithic structure 784. The insulating film 740 is provided with an insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon nitriding (SiON), or a so-called low-k material. The insulating film 740 may be, for example, a natural oxide film formed on the side surface of the monolithic structure 784, or may be a protective layer separately provided to protect the monolithic structure 784.
　ピニング層７４１は、第２領域７２０よりも不純物濃度が低い第２導電型の領域（例えば、Ｐ層）である。ピニング層７４１は、モノリシック構造７８４の側面と絶縁膜７４０との界面、及び第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面のうちの少なくとも１つ以上に設けられる。ピニング層７４１は、モノリシック構造７８４の側面と絶縁膜７４０との界面、又は第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面で生じた電荷が第３領域７３０の空乏層中に流れ込み、偽信号又は暗電流となることを抑制することができる。 The pinning layer 741 is a second conductive type region (for example, P layer) having an impurity concentration lower than that of the second region 720. The pinning layer 741 is provided at least one of the interface between the side surface of the monolithic structure 784 and the insulating film 740 and the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782. In the pinning layer 741, the electric charge generated at the interface between the side surface of the monolithic structure 784 and the insulating film 740 or the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782 flows into the depletion layer of the third region 730. , False signal or dark current can be suppressed.
　第６の構造例によれば、光検出装置７００Ｆは、モノリシック構造７８４が設けられた場合でも、偽信号又は暗電流の発生を抑制することができる。 According to the sixth structural example, the photodetector 700F can suppress the generation of a false signal or a dark current even when the monolithic structure 784 is provided.
　（第７の構造例）
　図８６は、第７の構造例に係る光検出装置７００Ｇの構造を示す縦断面図である。 (7th structural example)
FIG. 86 is a vertical cross-sectional view showing the structure of the photodetector 700G according to the seventh structural example.
　図８６に示すように、光検出装置７００Ｇは、第４の構造例に係る光検出装置７００Ｄに対して、光検出装置７００Ｇが形成される基板がシリコン基板等の半導体基板である点が異なる。このような場合、ピニング層７４１は、第３領域７３０を含む半導体基板と、絶縁膜７４０との界面に設けられてもよい。 As shown in FIG. 86, the photodetector 700G is different from the photodetector 700D according to the fourth structural example in that the substrate on which the photodetector 700G is formed is a semiconductor substrate such as a silicon substrate. In such a case, the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and the insulating film 740.
　第７の構造例によれば、光検出装置７００Ｇは、より安価な基板を用いることで、製造コストを低減することが可能である。 According to the seventh structural example, the photodetector 700G can reduce the manufacturing cost by using a cheaper substrate.
　（第８の構造例）
　図８７は、第８の構造例に係る光検出装置７００Ｈの構造を示す縦断面図である。 (8th structural example)
FIG. 87 is a vertical cross-sectional view showing the structure of the photodetector 700H according to the eighth structural example.
　図８７に示すように、光検出装置７００Ｈは、第６の構造例に係る光検出装置７００Ｆに対して、光検出装置７００Ｈが形成される基板が支持基板７８１を有しないＳＯＩ基板である点が異なる。このような場合、ピニング層７４１は、モノリシック構造７８４の側面と絶縁膜７４０との界面、及び第３領域７３０を含む半導体層とモノリシック構造７８４とのうちの少なくとも１つ以上に設けられ得る。 As shown in FIG. 87, the photodetector 700H is an SOI substrate on which the photodetector 700H is formed does not have a support substrate 781, as opposed to the photodetector 700F according to the sixth structural example. different. In such a case, the pinning layer 741 may be provided on at least one of the interface between the side surface of the monolithic structure 784 and the insulating film 740, and the semiconductor layer including the third region 730 and the monolithic structure 784.
　第８の構造例によれば、光検出装置７００Ｈは、全体の構成をより低背化することで、チップをより小型化することが可能である。 According to the eighth structural example, the photodetector 700H can make the chip smaller by lowering the overall configuration.
　（第９の構造例）
　図８８は、第９の構造例に係る光検出装置７００Ｉの構造を示す縦断面図である。 (9th structural example)
FIG. 88 is a vertical cross-sectional view showing the structure of the photodetector 700I according to the ninth structural example.
　図８８に示すように、光検出装置７００Ｉは、第２の構造例に係る光検出装置７００Ｂに対して、第１領域７１０が半導体基板の第２領域７２０が設けられた面と反対側の面に設けられる点が異なる。すなわち、光検出装置７００Ｉは、第２の構造例に係る光検出装置７００Ｂに対して、第１領域７１０、第３領域７３０、及び第２領域７２０が半導体基板の厚み方向に配列されている点が異なる。 As shown in FIG. 88, in the photodetector 700I, with respect to the photodetector 700B according to the second structural example, the first region 710 is the surface opposite to the surface on which the second region 720 of the semiconductor substrate is provided. The difference is that it is provided in. That is, in the photodetector 700I, the first region 710, the third region 730, and the second region 720 are arranged in the thickness direction of the semiconductor substrate with respect to the photodetector 700B according to the second structural example. Is different.
　具体的には、第２領域７２０は、半導体基板の第２面側に設けられる。一方、第１領域７１０は、半導体基板の第２領域７２０が設けられた第２面と反対側の第１面側に設けられる。第３領域７３０は、第３導電型の領域（例えば、ｉ層）であり、半導体基板の第１領域７１０及び第２領域７２０の間に設けられる。 Specifically, the second region 720 is provided on the second surface side of the semiconductor substrate. On the other hand, the first region 710 is provided on the first surface side opposite to the second surface on which the second region 720 of the semiconductor substrate is provided. The third region 730 is a third conductive type region (for example, layer i), and is provided between the first region 710 and the second region 720 of the semiconductor substrate.
　ここで、絶縁膜７４０は、半導体基板の第２領域７２０が設けられた第２面の上に設けられる。したがって、ピニング層７４１は、半導体基板の第２領域７２０が設けられた第２面と、絶縁膜７４０との界面に設けられてもよい。 Here, the insulating film 740 is provided on the second surface of the semiconductor substrate on which the second region 720 is provided. Therefore, the pinning layer 741 may be provided at the interface between the second surface provided with the second region 720 of the semiconductor substrate and the insulating film 740.
　第９の構造例によれば、光検出装置７００Ｉは、第１領域７１０、第３領域７３０、及び第２領域７２０を半導体基板の厚み方向に配列することができるため、チップ面積をより小さくすることが可能である。 According to the ninth structural example, the photodetector 700I can arrange the first region 710, the third region 730, and the second region 720 in the thickness direction of the semiconductor substrate, so that the chip area is made smaller. It is possible.
　（第１０の構造例）
　図８９は、第１０の構造例に係る光検出装置７００Ｊの構造を示す縦断面図である。 (10th structural example)
FIG. 89 is a vertical cross-sectional view showing the structure of the photodetector 700J according to the tenth structural example.
　図８９に示すように、光検出装置７００Ｊは、第９の構造例に係る光検出装置７００Ｉに対して、第２領域７２０が複数設けられる点が異なる。 As shown in FIG. 89, the photodetector 700J is different from the photodetector 700I according to the ninth structural example in that a plurality of second regions 720 are provided.
　具体的には、第２領域７２０は、半導体基板の第２面側に互いに離隔されて複数設けられる。また、第２領域７２０の各々の周囲の半導体基板の上には、ゲート絶縁膜７６２を介して制御ゲート７６１がそれぞれ設けられる。制御ゲート７１６は、第２領域７２０の両側に設けられてもよく、第２領域７２０の全周を囲むように設けられてもよい。 Specifically, a plurality of second regions 720 are provided on the second surface side of the semiconductor substrate so as to be separated from each other. Further, a control gate 761 is provided on the semiconductor substrate around each of the second regions 720 via a gate insulating film 762. The control gates 716 may be provided on both sides of the second region 720, or may be provided so as to surround the entire circumference of the second region 720.
　ここで、光検出装置７００Ｊでは、複数の第２領域７２０及び制御ゲート７６１の各々の間の領域が光吸収領域７３１であり、光吸収領域７３１の半導体基板の上に絶縁膜７４０が設けられる。したがって、ピニング層７４１は、半導体基板の光吸収領域７３１が設けられた第２面と、絶縁膜７４０との界面に設けられてもよい。 Here, in the photodetector 700J, the region between each of the plurality of second regions 720 and the control gate 761 is the light absorption region 731, and the insulating film 740 is provided on the semiconductor substrate of the light absorption region 731. Therefore, the pinning layer 741 may be provided at the interface between the second surface provided with the light absorption region 731 of the semiconductor substrate and the insulating film 740.
　第１０の構造例によれば、光検出装置７００Ｊは、第３領域７３０からより効率的に電流を取り出すことが可能である。 According to the tenth structural example, the photodetector 700J can more efficiently extract the current from the third region 730.
　（第１１の構造例）
　図９０は、第１１の構造例に係る光検出装置７００Ｋの構造を示す縦断面図である。 (11th structural example)
FIG. 90 is a vertical cross-sectional view showing the structure of the photodetector 700K according to the eleventh structural example.
　図９０に示すように、光検出装置７００Ｋは、第１領域７１０と、第１電極７１１と、第２領域７２０と、第２電極７２１と、第３領域７３０と、リセット領域７９１と、リセット電極７６６と、ゲート絶縁膜７６７と、グランド領域７９２と、グランド電極７６５と、面内分離層７５３と、ピニング層７４１とを備える。 As shown in FIG. 90, the photodetector 700K includes a first region 710, a first electrode 711, a second region 720, a second electrode 721, a third region 730, a reset region 791, and a reset electrode. It includes a 766, a gate insulating film 767, a ground region 792, a ground electrode 765, an in-plane separation layer 753, and a pinning layer 741.
　第１領域７１０、第１電極７１１、第２領域７２０、第２電極７２１、及び第３領域７３０については、第１の構造例に係る光検出装置７００Ａなどにて説明した通りであるため、ここでの説明は省略する。なお、光検出装置７００Ｋでは、第１領域７１０、第１電極７１１、第２領域７２０、及び第２電極７２１は、半導体基板の同一面側に設けられる。 The first region 710, the first electrode 711, the second region 720, the second electrode 721, and the third region 730 are as described in the photodetector 700A and the like according to the first structural example. The explanation in is omitted. In the photodetector 700K, the first region 710, the first electrode 711, the second region 720, and the second electrode 721 are provided on the same surface side of the semiconductor substrate.
　リセット領域７９１は、第１導電型の領域（例えば、Ｎ＋層）である。リセット領域７９１の上には、ゲート絶縁膜７６７を介してリセット電極７６６が設けられる。リセット領域７９１は、リセット電極７６６からの電圧印加によって、第３領域７３０の内部に残存する電荷を第３領域７３０の外部に排出することができる。リセット領域７９１は、第２領域７２０の両側に設けられてもよく、第２領域７２０の周囲を囲むように設けられてもよい。 The reset region 791 is a first conductive type region (for example, N + layer). A reset electrode 766 is provided on the reset region 791 via a gate insulating film 767. By applying a voltage from the reset electrode 766, the reset region 791 can discharge the electric charge remaining inside the third region 730 to the outside of the third region 730. The reset area 791 may be provided on both sides of the second area 720, or may be provided so as to surround the circumference of the second area 720.
　グランド領域７９２は、第２導電型の領域（例えば、Ｐ＋層）である。グランド領域７９２は、グランド電極７６５と電気的に接続され、第３領域７３０にグランド電位を供給する。グランド領域７９２は、第１領域７１０及び第２領域７２０と互いに離隔されて設けられてもよい。 The ground region 792 is a second conductive type region (for example, P + layer). The ground region 792 is electrically connected to the ground electrode 765 to supply the ground potential to the third region 730. The ground region 792 may be provided so as to be separated from the first region 710 and the second region 720.
　面内分離層７５３は、第３領域７３０を含む半導体基板の同一面側に設けられた第１領域７１０、第２領域７２０、リセット領域７９１、及びグランド領域７９２の各々の間に設けられる。面内分離層７５３は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体で形成され、第１領域７１０、第２領域７２０、リセット領域７９１、及びグランド領域７９２の各々を互いに電気的に分離する。面内分離層７５３は、第１領域７１０、第２領域７２０、リセット領域７９１、及びグランド領域７９２の各々の形成深さよりも深い領域まで延在して設けられてもよい。 The in-plane separation layer 753 is provided between each of the first region 710, the second region 720, the reset region 791, and the ground region 792 provided on the same side of the semiconductor substrate including the third region 730. The in-plane separation layer 753 is formed of an insulator such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material, and has a first region 710 and a second region. Each of the 720, the reset region 791, and the ground region 792 is electrically separated from each other. The in-plane separation layer 753 may be provided extending to a region deeper than the formation depth of each of the first region 710, the second region 720, the reset region 791, and the ground region 792.
　光検出装置７００Ｋでは、ピニング層７４１は、第３領域７３０を含む半導体基板と、絶縁体である面内分離層７５３の各々との界面に設けられてもよい。具体的には、ピニング層７４１は、半導体基板に埋め込まれた面内分離層７５３の側面及び底面を覆うように設けられてもよい。 In the photodetector 700K, the pinning layer 741 may be provided at the interface between the semiconductor substrate including the third region 730 and each of the in-plane separation layers 753 which are insulators. Specifically, the pinning layer 741 may be provided so as to cover the side surface and the bottom surface of the in-plane separation layer 753 embedded in the semiconductor substrate.
　第１１の構造例によれば、光検出装置７００Ｋは、偽信号又は暗電流の発生を抑制すると共に、電極間の電気的な分離性を向上させることができる。 According to the eleventh structural example, the photodetector 700K can suppress the generation of false signals or dark currents and improve the electrical separability between the electrodes.
　（第１２の構造例）
　図９１は、第１２の構造例に係る光検出装置７００Ｌの構造を示す縦断面図である。 (12th structural example)
FIG. 91 is a vertical cross-sectional view showing the structure of the photodetector 700L according to the twelfth structural example.
　図９１に示すように、光検出装置７００Ｌは、例えば、第１領域７１０と、第２領域７２０と、第３領域７３０と、第１電極７１１と、ビア７１２と、第１面絶縁層７５１と、画素分離層７５０と、第２電極７２１と、制御ゲート７６１と、ゲート絶縁膜７６２とを備える。 As shown in FIG. 91, the photodetector 700L includes, for example, a first region 710, a second region 720, a third region 730, a first electrode 711, a via 712, and a first surface insulating layer 751. A pixel separation layer 750, a second electrode 721, a control gate 761, and a gate insulating film 762 are provided.
　第１領域７１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域７２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域７３０は、シリコン（Ｓｉ）などの半導体基板の第１領域７１０と第２領域７２０との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 710 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 720 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The third region 730 is a third conductive type region (for example, layer i) provided between the first region 710 and the second region 720 of a semiconductor substrate such as silicon (Si).
　第１電極７１１は、半導体基板の第１面の上に第１面絶縁層７５１を介して設けられ、第１面絶縁層７５１を貫通するビア７１２等を介して第１領域７１０と電気的に接続する。第１電極７１１は、例えば、カソード電極として機能する。第１電極７１１は、例えば、画素同士の境界に沿って画素分離層７５０を跨ぐように設けられ、画素ごとに設けられたビア７１２にて、各画素の第１領域７１０と電気的に接続する。 The first electrode 711 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 751, and is electrically connected to the first region 710 via a via 712 or the like penetrating the first surface insulating layer 751. Connecting. The first electrode 711 functions as, for example, a cathode electrode. The first electrode 711 is provided, for example, so as to straddle the pixel separation layer 750 along the boundary between pixels, and is electrically connected to the first region 710 of each pixel by a via 712 provided for each pixel. ..
　画素分離層７５０は、半導体基板を厚み方向に貫通して設けられ、半導体基板の面内方向に複数設けられた画素の各々を互いに電気的に離隔する。画素分離層７５０は、例えば、半導体基板の面内方向に行列状に配列された各画素の境界に沿って、格子状に設けられてもよい。 The pixel separation layer 750 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other. The pixel separation layer 750 may be provided in a grid pattern, for example, along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
　第２電極７２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域７２０と電気的に接続する。第２電極７２１は、例えば、アノード電極として機能する。 The second electrode 721 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 720. The second electrode 721 functions as, for example, an anode electrode.
　制御ゲート７６１は、半導体基板の第２面の上にゲート絶縁膜７６２を介して設けられるゲート電極である。制御ゲート７６１は、電圧印加によって、第３領域７３０におけるポテンシャル障壁を制御することができる。 The control gate 761 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 762. The control gate 761 can control the potential barrier in the third region 730 by applying a voltage.
　第１電極７１１、ビア７１２、第２電極７２１、及び制御ゲート７６１は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。第１面絶縁層７５１、画素分離層７５０、及びゲート絶縁膜７６２は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 711, via 712, second electrode 721, and control gate 761 are made of a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta). It may be provided by polysilicon (poly-Si) or other conductive material. The first surface insulating layer 751, the pixel separation layer 750, and the gate insulating film 762 are made of an insulator such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), or a so-called low-k material. It may be provided.
　光検出装置７００Ｌでは、ピニング層７４１は、画素分離層７５０と第３領域７３０との界面に設けられてもよい。具体的には、ピニング層７４１は、画素分離層７５０の側面を覆うように設けられてもよい。 In the photodetector 700L, the pinning layer 741 may be provided at the interface between the pixel separation layer 750 and the third region 730. Specifically, the pinning layer 741 may be provided so as to cover the side surface of the pixel separation layer 750.
　第１２の構造例によれば、光検出装置７００Ｌは、裏面照射型の画素アレイ構造として設けられた場合でも、偽信号又は暗電流の発生を抑制することができる。 According to the twelfth structural example, the photodetector 700L can suppress the generation of false signals or dark currents even when it is provided as a back-illuminated pixel array structure.
　（第１３の構造例）
　図９２は、第１３の構造例に係る光検出装置７００Ｍの構造を示す縦断面図である。図９３Ａ及び図９３Ｂは、第１３の構造例に係る光検出装置７００Ｍの平面構造の一例を示す上面図である。図９２にて示す光検出装置７００Ｍの断面構造は、図９３Ａ及び図９３ＢのＡ－ＡＡ切断面における断面構造に対応する。 (13th structural example)
FIG. 92 is a vertical cross-sectional view showing the structure of the photodetector 700M according to the thirteenth structural example. 93A and 93B are top views showing an example of the planar structure of the photodetector 700M according to the thirteenth structural example. The cross-sectional structure of the photodetector 700M shown in FIG. 92 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 93A and 93B.
　図９２、図９３Ａ、及び図９３Ｂに示すように、第１３の構造例は、第１の構造例における第２導電型のピニング層７４１を負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでは、ピニング層７４２以外の構成の詳細な説明は省略する。なお、ピニング層７４２は、図９２に示すように半導体基板の上に積層されていてもよく、後述する図９６に示すように半導体基板の内側に埋め込まれていてもよい。 As shown in FIGS. 92, 93A, and 93B, the thirteenth structural example replaces the second conductive type pinning layer 741 in the first structural example with a pinning layer 742 having a negative fixed charge or chargeability. Corresponds to the structure. Therefore, detailed description of configurations other than the pinning layer 742 will be omitted here. The pinning layer 742 may be laminated on the semiconductor substrate as shown in FIG. 92, or may be embedded inside the semiconductor substrate as shown in FIG. 96 described later.
　ピニング層７４２は、負の固定電荷を有する層、又は負の帯電性を有する層である。このようなピニング層７４２は、例えば、酸化シリコン（ＳｉＯ２）、窒化シリコン（ＳｉＮ）、酸窒化シリコン（ＳｉＯＮ）、酸化ハフニウム（ＨｆＯ２）、酸化アルミニウム（Ａｌ２Ｏ３）、酸化ジルコニウム（ＺｒＯ２）、酸化タンタル（Ｔａ２Ｏ５）、酸化チタン（ＴｉＯ２）、酸化ランタン（Ｌａ２Ｏ３）、酸化プラセオジム（Ｐｒ２Ｏ３）、酸化セリウム（ＣｅＯ２）、酸化ネオジム（Ｎｄ２Ｏ３）、酸化プロメチウム（Ｐｍ２Ｏ３）、酸化サマリウム（Ｓｍ２Ｏ３）、酸化ユウロピウム（Ｅｕ２Ｏ３）、酸化ガドリニウム（Ｇｄ２Ｏ３）、酸化テルビウム（Ｔｂ２Ｏ３）、酸化ジスプロシウム（Ｄｙ２Ｏ３）、酸化ホルミウム（Ｈｏ２Ｏ３）、酸化ツリウム（Ｔｍ２Ｏ３）、酸化イッテルビウム（Ｙｂ２Ｏ３）、酸化ルテチウム（Ｌｕ２Ｏ３）、酸化イットリウム（Ｙ２Ｏ３）、又は各種樹脂などで形成することができる。また、ピニング層７４２は、上記材料の複数を組み合わせて積層した多層膜として形成されてもよい。なお、ピニング層７４２は、負の固定電荷を有する、又は負の帯電性を有する絶縁材料であれば、他の材料にて形成されてもよい。 The pinning layer 742 is a layer having a negative fixed charge or a layer having a negative charge. Such a pinning layer 742 includes, for example, silicon oxide (SiO 2 ), silicon nitride (SiN), silicon oxynitride (SiON), hafnium oxide (HfO 2 ), aluminum oxide (Al 2 O 3 ), zirconium oxide (ZrO). 2 ), Tantal Oxide (Ta 2 O 5 ), Titanium Oxide (TIO 2 ), Lantern Oxide (La 2 O 3 ), Placeodym Oxide (Pr 2 O 3 ), Cerium Oxide (CeO 2 ), Neodymium Oxide (Nd 2 O 3 ), Promethium oxide (Pm 2 O 3 ), Samalium oxide (Sm 2 O 3 ), Europium oxide (Eu 2 O 3 ), Gadolinium oxide (Gd 2 O 3 ), Terbium oxide (Tb 2 O 3 ), Disprosium oxide (Dy 2) O 3 ), formium oxide (Ho 2 O 3 ), thurium oxide (Tm 2 O 3 ), ytterbium oxide (Yb 2 O 3 ), lutetium oxide (Lu 2 O 3 ), yttrium oxide (Y 2 O 3 ), or It can be formed of various resins and the like. Further, the pinning layer 742 may be formed as a multilayer film in which a plurality of the above materials are combined and laminated. The pinning layer 742 may be formed of any other material as long as it is an insulating material having a negative fixed charge or a negative charge.
　第１３の構造例によれば、光検出装置７００Ｍは、偽信号又は暗電流の発生を抑制することができる。 According to the thirteenth structural example, the photodetector 700M can suppress the generation of false signals or dark currents.
　（第１４の構造例）
　図９４は、第１４の構造例に係る光検出装置７００Ｎの構造を示す縦断面図である。図９５Ａ及び図９５Ｂは、第１４の構造例に係る光検出装置７００Ｎの平面構造の一例を示す上面図である。図９４にて示す光検出装置７００Ｎの断面構造は、図９５Ａ及び図９５ＢのＡ－ＡＡ切断面における断面構造に対応する。 (14th structural example)
FIG. 94 is a vertical cross-sectional view showing the structure of the photodetector 700N according to the 14th structural example. 95A and 95B are top views showing an example of the planar structure of the photodetector 700N according to the 14th structural example. The cross-sectional structure of the photodetector 700N shown in FIG. 94 corresponds to the cross-sectional structure at the AA cut surface of FIGS. 95A and 95B.
　図９４～図９５Ｂに示すように、第１４の構造例は、第２の構造例における第２導電型のピニング層７４１を、第１３の構造例にて説明した負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでの各構成の詳細な説明は省略する。なお、ピニング層７４２は、図９４に示すように半導体基板の上に積層されていてもよく、後述する図９６に示すように半導体基板の内側に埋め込まれていてもよい。 As shown in FIGS. 94 to 95B, in the fourteenth structural example, the second conductive type pinning layer 741 in the second structural example has a negative fixed charge or chargeability described in the thirteenth structural example. Corresponds to the structure replaced with the pinning layer 742 having. Therefore, detailed description of each configuration here will be omitted. The pinning layer 742 may be laminated on the semiconductor substrate as shown in FIG. 94, or may be embedded inside the semiconductor substrate as shown in FIG. 96 described later.
　第１４の構造例によれば、光検出装置７００Ｎは、半導体基板と絶縁膜７４０との界面で生じた電子によって偽信号又は暗電流が発生することをさらに抑制することができる。 According to the 14th structural example, the photodetector 700N can further suppress the generation of false signals or dark currents due to the electrons generated at the interface between the semiconductor substrate and the insulating film 740.
　（第１５の構造例）
　図９６は、第１５の構造例に係る光検出装置７００Ｏの構造を示す縦断面図である。図９７Ａ、図９７Ｂ、図９９Ａ、及び図９９Ｂは、第３領域７３０を含む半導体層の表面側においてピニング層７４２が形成される領域の一例を示す平面図である。図９８Ａ、図９８Ｂ、図１００Ａ、及び図１００Ｂは、第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面においてピニング層７４２が形成される領域の一例を示す平面図である。なお、図９６にて示す光検出装置７００Ｏの断面構造は、図９７Ａ～図１００ＢのＡ－ＡＡ切断面における断面構造に対応する。 (15th structural example)
FIG. 96 is a vertical cross-sectional view showing the structure of the photodetector 700O according to the fifteenth structural example. 97A, 97B, 99A, and 99B are plan views showing an example of a region in which the pinning layer 742 is formed on the surface side of the semiconductor layer including the third region 730. 98A, 98B, 100A, and 100B are plan views showing an example of a region in which the pinning layer 742 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782. The cross-sectional structure of the photodetector 700O shown in FIG. 96 corresponds to the cross-sectional structure of the AA cut surface of FIGS. 97A to 100B.
　図９６～図１００Ｂに示すように、第１５の構造例は、第３の構造例における第２導電型のピニング層７４１を、第１３の構造例にて説明した負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでの各構成の詳細な説明は省略する。なお、ピニング層７４２は、図９６に示すように半導体基板の内側に埋め込まれていてもよく、前述した図９２及び図９４に示すように半導体基板の上に積層されていてもよい。 As shown in FIGS. 96 to 100B, in the fifteenth structural example, the second conductive type pinning layer 741 in the third structural example has a negative fixed charge or chargeability described in the thirteenth structural example. Corresponds to the structure replaced with the pinning layer 742 having. Therefore, detailed description of each configuration here will be omitted. The pinning layer 742 may be embedded inside the semiconductor substrate as shown in FIG. 96, or may be laminated on the semiconductor substrate as shown in FIGS. 92 and 94 described above.
　第１５の構造例によれば、光検出装置７００Ｏは、形成された基板がＳＯＩ基板であっても、偽信号又は暗電流の発生を抑制することができる。 According to the fifteenth structural example, the photodetector 700O can suppress the generation of false signals or dark currents even if the formed substrate is an SOI substrate.
　（第１６の構造例）
　図１０１は、第１６の構造例に係る光検出装置７００Ｐの構造を示す縦断面図である。図１０２Ａ、図１０２Ｂ、図１０４Ａ、及び図１０４Ｂは、電荷生成層７８３の表面側においてピニング層７４２が形成される領域の一例を示す平面図である。図１０３Ａ、図１０３Ｂ、図１０５Ａ、及び図１０５Ｂは、第３領域７３０を含む半導体層と埋め込み絶縁膜７８２との界面においてピニング層７４２が形成される領域の一例を示す平面図である。なお、図１０１にて示す光検出装置７００Ｐの断面構造は、図１０２Ａ～図１０５ＢのＡ－ＡＡ切断面における断面構造に対応する。 (16th structural example)
FIG. 101 is a vertical cross-sectional view showing the structure of the photodetector 700P according to the sixteenth structural example. 102A, 102B, 104A, and 104B are plan views showing an example of a region where the pinning layer 742 is formed on the surface side of the charge generation layer 783. 103A, 103B, 105A, and 105B are plan views showing an example of a region in which the pinning layer 742 is formed at the interface between the semiconductor layer including the third region 730 and the embedded insulating film 782. The cross-sectional structure of the photodetector 700P shown in FIG. 101 corresponds to the cross-sectional structure of the AA cut surface in FIGS. 102A to 105B.
　図１０１～図１０５Ｂに示すように、第１６の構造例は、第４の構造例における第２導電型のピニング層７４１を、第１３の構造例にて説明した負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでの各構成の詳細な説明は省略する。なお、ピニング層７４２は、図１０１に示すように電荷生成層７８３の内側に埋め込まれていてもよく、前述した図９２及び図９４に示すように電荷生成層７８３の上に積層されていてもよい。 As shown in FIGS. 101 to 105B, in the sixteenth structural example, the second conductive type pinning layer 741 in the fourth structural example has a negative fixed charge or chargeability described in the thirteenth structural example. Corresponds to the structure replaced with the pinning layer 742 having. Therefore, detailed description of each configuration here will be omitted. The pinning layer 742 may be embedded inside the charge generation layer 783 as shown in FIG. 101, or may be laminated on the charge generation layer 783 as shown in FIGS. 92 and 94 described above. Good.
　第１６の構造例によれば、光検出装置７００Ｐは、入射光に対する光電変換特性を向上させることができる。 According to the 16th structural example, the photodetector 700P can improve the photoelectric conversion characteristic with respect to the incident light.
　（第１７の構造例）
　図１０６は、第１７の構造例に係る光検出装置７００Ｑの構造を示す縦断面図である。 (17th structural example)
FIG. 106 is a vertical cross-sectional view showing the structure of the photodetector 700Q according to the 17th structural example.
　図１０６に示すように、第１７の構造例は、第１１の構造例における第２導電型のピニング層７４１を、第１３の構造例にて説明した負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでの各構成の詳細な説明は省略する。 As shown in FIG. 106, in the 17th structural example, the second conductive type pinning layer 741 in the 11th structural example is the pinning layer having a negative fixed charge or chargeability described in the 13th structural example. Corresponds to the structure replaced by 742. Therefore, detailed description of each configuration here will be omitted.
　第１７の構造例によれば、光検出装置７００Ｑは、偽信号又は暗電流の発生を抑制すると共に、電極間の電気的な分離性を向上させることができる。 According to the 17th structural example, the photodetector 700Q can suppress the generation of false signals or dark currents and improve the electrical separability between the electrodes.
　（第１８の構造例）
　図１０７は、第１８の構造例に係る光検出装置７００Ｒの構造を示す縦断面図である。 (18th structural example)
FIG. 107 is a vertical cross-sectional view showing the structure of the photodetector 700R according to the eighteenth structural example.
　図１０７に示すように、第１８の構造例は、第１２の構造例における第２導電型のピニング層７４１を、第１３の構造例にて説明した負の固定電荷又は帯電性を有するピニング層７４２に置き換えた構造に対応する。したがって、ここでの各構成の詳細な説明は省略する。 As shown in FIG. 107, in the eighteenth structural example, the second conductive type pinning layer 741 in the twelfth structural example is the pinning layer having a negative fixed charge or chargeability described in the thirteenth structural example. Corresponds to the structure replaced by 742. Therefore, detailed description of each configuration here will be omitted.
　第１８の構造例によれば、光検出装置７００Ｒは、裏面照射型の画素アレイ構造として設けられた場合でも、偽信号又は暗電流の発生を抑制することができる。 According to the eighteenth structural example, the photodetector 700R can suppress the generation of false signals or dark currents even when it is provided as a back-illuminated pixel array structure.
　＜６．第６の実施形態＞
　（基本構造）
　次に、図１０８Ａ～図１１０を参照して、本開示の第６の実施形態に係る光検出装置の基本構造について説明する。図１０８Ａは、本実施形態に係る光検出装置８００の構造を示す第２面側から見た平面図である。図１０８Ｂは、図１０８ＡのＡ－ＡＡ切断面における光検出装置８００の構造を示す縦断面図である。図１０８Ｃは、図１０８ＡのＢ－ＢＢ切断面における光検出装置８００の構造を示す縦断面図である。図１０９は、光検出装置８００が備える画素回路に含まれる画素トランジスタの配置の一例を示す平面図である。図１１０は、ＤＰＤセンサ及びＰＤとして機能する光検出装置８００が備える画素回路の等価回路の一例を示す回路図である。 <6. Sixth Embodiment>
(Basic structure)
Next, the basic structure of the photodetector according to the sixth embodiment of the present disclosure will be described with reference to FIGS. 108A to 110. FIG. 108A is a plan view of the photodetector 800 according to the present embodiment as viewed from the second surface side. FIG. 108B is a vertical cross-sectional view showing the structure of the photodetector 800 on the AA cut surface of FIG. 108A. FIG. 108C is a vertical cross-sectional view showing the structure of the photodetector 800 on the B-BB cut surface of FIG. 108A. FIG. 109 is a plan view showing an example of arrangement of pixel transistors included in the pixel circuit included in the photodetector 800. FIG. 110 is a circuit diagram showing an example of an equivalent circuit of a pixel circuit included in the DPD sensor and the photodetector 800 that functions as a PD.
　図１０８Ａ～図１０８Ｃに示すように、光検出装置８００は、例えば、第１領域８１０と、第２領域８２０と、第３領域８３０と、第１電極８１１と、第２電極８２１と、制御ゲートＣＧと、第１導電型領域８９１と、転送ゲートＴＲＧと、フローティングディフュージョンＦＤと、取出電極８９３とを備える。 As shown in FIGS. 108A to 108C, the photodetector 800 includes, for example, a first region 810, a second region 820, a third region 830, a first electrode 811 and a second electrode 821, and a control gate. It includes a CG, a first conductive region 891, a transfer gate TRG, a floating diffusion FD, and an extraction electrode 893.
　第１領域８１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域８２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第２領域８２０は、例えば、矩形形状の画素領域の略中央に島状に設けられてもよい。第３領域８３０は、シリコン（Ｓｉ）などの半導体基板の第１領域８１０と第２領域８２０との間に設けられ、第１領域８１０よりも導電型不純物の濃度が低い第１導電型の領域（例えば、Ｎ－層）である。 The first region 810 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 820 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The second region 820 may be provided, for example, in an island shape substantially in the center of the rectangular pixel region. The third region 830 is provided between the first region 810 and the second region 820 of the semiconductor substrate such as silicon (Si), and is a first conductive type region having a lower concentration of conductive impurities than the first region 810. (For example, N-layer).
　第１電極８１１は、半導体基板の第１面の上に設けられ、第１領域８１０と電気的に接続する。第１電極８１１は、例えば、カソード電極として機能する。第２電極８２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域８２０と電気的に接続する。第２電極８２１は、例えば、アノード電極として機能する。 The first electrode 811 is provided on the first surface of the semiconductor substrate and is electrically connected to the first region 810. The first electrode 811 functions as, for example, a cathode electrode. The second electrode 821 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 820. The second electrode 821 functions as, for example, an anode electrode.
　制御ゲートＣＧは、半導体基板の第２面の上にゲート絶縁膜（図示せず）を介して設けられるゲート電極である。制御ゲートＣＧは、電圧印加によって、第３領域８３０におけるポテンシャル障壁を制御することができる。制御ゲートＣＧは、例えば、半導体基板の面内の第１方向（すなわち、図１０８ＡのＡ－ＡＡ切断面の延在方向）にて第２領域８２０を挟んで両側に設けられてもよい。 The control gate CG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown). The control gate CG can control the potential barrier in the third region 830 by applying a voltage. The control gate CG may be provided on both sides of the second region 820 in the first direction in the plane of the semiconductor substrate (that is, the extending direction of the AA cut surface of FIG. 108A).
　第１導電型領域８９１は、半導体基板の第２面側に設けられた第１導電型の領域（例えば、Ｎ層）である。第１導電型領域８９１は、例えば、第１領域８１０よりも導電型不純物の濃度が低く、第３領域８３０よりも導電型不純物の濃度が高くなるように設けられる。第１導電型領域８９１は、第２領域８２０から半導体基板の面内の第１方向と直交する第２方向（すなわち、図１０８ＡのＢ－ＢＢ切断面の延在方向）に延在して設けられる。 The first conductive type region 891 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate. The first conductive region 891 is provided, for example, so that the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830. The first conductive type region 891 extends from the second region 820 in the second direction orthogonal to the first direction in the plane of the semiconductor substrate (that is, the extending direction of the B-BB cut surface of FIG. 108A). Be done.
　フローティングディフュージョンＦＤは、第２領域８２０よりも導電型不純物の濃度が高い第２導電型の領域（例えば、Ｐ＋＋層）であり、半導体基板の第２面側に設けられる。フローティングディフュージョンＦＤは、第２領域８２０から第２方向に延在する第１導電型領域８９１の端部側に設けられてもよい。 The floating diffusion FD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate. The floating diffusion FD may be provided on the end side of the first conductive type region 891 extending in the second direction from the second region 820.
　転送ゲートＴＲＧは、半導体基板の第２面の上にゲート絶縁膜（図示せず）を介して設けられるゲート電極である。転送ゲートＴＲＧは、第２領域８２０と、フローティングディフュージョンＦＤとの間に設けられ、電圧印加によって第２領域８２０からフローティングディフュージョンＦＤへ電荷を転送する。 The transfer gate TRG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown). The transfer gate TRG is provided between the second region 820 and the floating diffusion FD, and transfers the electric charge from the second region 820 to the floating diffusion FD by applying a voltage.
　ここで、第１導電型領域８９１は、転送ゲートＴＲＧの下方の領域、及びフローティングディフュージョンＦＤが設けられた領域を囲む領域に設けられてもよい。これによれば、第１導電型領域８９１は、第２領域８２０からフローティングディフュージョンＦＤへ電荷を転送するチャネルとして機能することができる。また、第１導電型領域８９１は、第３領域８３０にて光電変換された電荷がフローティングディフュージョンＦＤに直接入り込むことを防止することができる。 Here, the first conductive type region 891 may be provided in a region below the transfer gate TRG and a region surrounding a region in which the floating diffusion FD is provided. According to this, the first conductive type region 891 can function as a channel for transferring charges from the second region 820 to the floating diffusion FD. Further, the first conductive type region 891 can prevent the charge photoelectrically converted in the third region 830 from directly entering the floating diffusion FD.
　取出電極８９３は、半導体基板の第１面の上に設けられ、フローティングディフュージョンＦＤと電気的に接続する。取出電極８９３は、フローティングディフュージョンＦＤに蓄積された電荷を画素回路等に出力することができる。 The take-out electrode 893 is provided on the first surface of the semiconductor substrate and is electrically connected to the floating diffusion FD. The take-out electrode 893 can output the electric charge accumulated in the floating diffusion FD to a pixel circuit or the like.
　第１電極８１１、第２電極８２１、制御ゲートＣＧ、転送ゲートＴＲＧ、及び取出電極８９３は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。 The first electrode 811, the second electrode 821, the control gate CG, the transfer gate TRG, and the take-out electrode 893 are, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta). ), Polysilicon (poly-Si), or other conductive material.
　したがって、図１０８Ａ及び図１０８Ｂに示すように、光検出装置８００は、第１領域８１０、第２領域８２０、第３領域８３０、第１電極８１１、第２電極８２１、及び制御ゲートＣＧを備える。これにより、光検出装置８００は、ＤＰＤ（Ｄｙｎａｍｉｃ　ＰｈｏｔｏＤｉｏｄｅ）センサとして機能することができる。 Therefore, as shown in FIGS. 108A and 108B, the photodetector 800 includes a first region 810, a second region 820, a third region 830, a first electrode 811, a second electrode 821, and a control gate CG. As a result, the photodetector 800 can function as a DPD (Dynamic Photodiode) sensor.
　また、図１０８Ａ及び図１０８Ｃに示すように、光検出装置８００は、第１領域８１０、第２領域８２０、第３領域８３０、第１電極８１１、第１導電型領域８９１、転送ゲートＴＲＧ、フローティングディフュージョンＦＤ、及び取出電極８９３を備える。これにより、光検出装置８００は、通常のＰＤ（ＰｈｏｔｏＤｉｏｄｅ）として機能することができる。 Further, as shown in FIGS. 108A and 108C, the photodetector 800 includes a first region 810, a second region 820, a third region 830, a first electrode 811, a first conductive region 891, a transfer gate TRG, and a floating region. It includes a diffusion FD and an extraction electrode 893. As a result, the photodetector 800 can function as a normal PD (Photodiode).
　ここで、光検出装置８００が通常のＰＤとして機能する際にフローティングディフュージョンＦＤから取り出された電荷は、画素回路にて信号処理されることで画素信号に変換される。 Here, the electric charge taken out from the floating diffusion FD when the photodetector 800 functions as a normal PD is converted into a pixel signal by signal processing in the pixel circuit.
　図１１０にて光検出装置８００が備える画素回路の等価回路図を示す。なお、図１１０におけるＤＰＤ／ＰＤは、第１領域８１０、第３領域８３０、及び第２領域８２０によるＰＩＮダイオード構造の光電変換部を示す。 FIG. 110 shows an equivalent circuit diagram of a pixel circuit included in the photodetector 800. Note that the DPD / PD in FIG. 110 indicates a photoelectric conversion unit having a PIN diode structure with a first region 810, a third region 830, and a second region 820.
　図１１０に示すように、ＤＰＤセンサの画素回路は、光電変換部ＤＰＤ、及びスイッチトランジスタＳＷを含む。ＤＰＤセンサの画素回路では、光電変換部ＤＰＤは、スイッチトランジスタＳＷを介して電源Ｖａと電気的に接続される。 As shown in FIG. 110, the pixel circuit of the DPD sensor includes a photoelectric conversion unit DPD and a switch transistor SW. In the pixel circuit of the DPD sensor, the photoelectric conversion unit DPD is electrically connected to the power supply Va via the switch transistor SW.
　ＰＤの画素回路は、光電変換部ＰＤ、転送トランジスタＴＲＧ、フローティングディフュージョンＦＤ、リセットトランジスタＲＳＴ、アンプトランジスタＡＭＰ、及び選択トランジスタＳＥＬを含む。ＰＤの画素回路では、光電変換部ＰＤは、転送トランジスタＴＲＧを介して、フローティングディフュージョンＦＤに電気的に接続される。また、フローティングディフュージョンＦＤには、さらにリセットトランジスタＲＳＴを介して電源Ｖｄが接続され、かつアンプトランジスタＡＭＰのゲートが接続される。アンプトランジスタＡＭＰのドレインは、電源Ｖｄに接続され、アンプトランジスタＡＭＰのソースは、選択トランジスタＳＥＬを介して外部出力Ｏｕｔｐｕｔに接続される。なお、ＤＰＤセンサ側の電源Ｖａと、ＰＤ側の電源Ｖｄとは、互いに異なる電源であってもよく、同一の電源であってもよい。 The pixel circuit of PD includes a photoelectric conversion unit PD, a transfer transistor TRG, a floating diffusion FD, a reset transistor RST, an amplifier transistor AMP, and a selection transistor SEL. In the pixel circuit of the PD, the photoelectric conversion unit PD is electrically connected to the floating diffusion FD via the transfer transistor TRG. Further, the power supply Vd is further connected to the floating diffusion FD via the reset transistor RST, and the gate of the amplifier transistor AMP is also connected. The drain of the amplifier transistor AMP is connected to the power supply Vd, and the source of the amplifier transistor AMP is connected to the external output Output via the selection transistor SEL. The power supply Va on the DPD sensor side and the power supply Vd on the PD side may be different power supplies or the same power supply.
　このような画素回路を備えることにより、光検出装置８００は、ＤＰＤセンサ及びＰＤの両方として機能することが可能である。 By providing such a pixel circuit, the photodetector 800 can function as both a DPD sensor and a PD.
　また、図１０９に示すように、上述した画素回路に含まれる画素トランジスタの少なくともいずれか１つ以上は、光検出装置８００の画素トランジスタ領域Ｔｒに形成されてもよい。具体的には、リセットトランジスタＲＳＴ、アンプトランジスタＡＭＰ、選択トランジスタＳＥＬ、又はスイッチトランジスタＳＷは、画素領域の第１方向（すなわち、図１０８ＡのＡ－ＡＡ切断面の延在方向）の両端部に設けられた画素トランジスタ領域Ｔｒに形成されてもよい。 Further, as shown in FIG. 109, at least one or more of the pixel transistors included in the pixel circuit described above may be formed in the pixel transistor region Tr of the photodetector 800. Specifically, the reset transistor RST, the amplifier transistor AMP, the selection transistor SEL, or the switch transistor SW are provided at both ends of the pixel region in the first direction (that is, the extending direction of the AA cut surface of FIG. 108A). It may be formed in the pixel transistor region Tr.
　例えば、転送ゲートＴＲＧを挟んで一方の側の画素トランジスタ領域Ｔｒには、リセットトランジスタＲＳＴ、及びアンプトランジスタＡＭＰが形成されてもよい。また、転送ゲートＴＲＧを挟んで他方の側の画素トランジスタ領域Ｔｒには、選択トランジスタＳＥＬ、及びスイッチトランジスタＳＷが形成されてもよい。 For example, a reset transistor RST and an amplifier transistor AMP may be formed in the pixel transistor region Tr on one side of the transfer gate TRG. Further, the selection transistor SEL and the switch transistor SW may be formed in the pixel transistor region Tr on the other side of the transfer gate TRG.
　（動作例）
　続いて、図１１１～図１１３Ｃを参照して、本実施形態に係る光検出装置８００のＴｏＦ（Ｔｉｍｅ　ｏｆ　Ｆｌｉｇｈｔ）センサとしての動作例について説明する。 (Operation example)
Subsequently, with reference to FIGS. 111 to 113C, an operation example of the photodetector 800 according to the present embodiment as a ToF (Time of Flight) sensor will be described.
　図１１１は、本実施形態に係る光検出装置８００のＴｏＦセンサ動作の一例を示すタイミングチャート図である。図１１２は、ＴｏＦセンサに用いられる光源を説明する説明図である。図１１３Ａは、図１１１の（１）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１１３Ｂは、図１１１の（２）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１１３Ｃは、図１１１の（３）のタイミングにおける光検出装置８００の状態を説明する縦断面図である。 FIG. 111 is a timing chart showing an example of the ToF sensor operation of the photodetector 800 according to the present embodiment. FIG. 112 is an explanatory diagram illustrating a light source used in the ToF sensor. FIG. 113A is a vertical sectional view illustrating the state of the photodetector 800 at the timing of FIG. 111 (1), and FIG. 113B describes the state of the photodetector 800 at the timing of FIG. 111 (2). FIG. 113C is a vertical cross-sectional view for explaining the state of the photodetector 800 at the timing of FIG. 111 (3).
　図１１１及び図１１３Ａに示すように、まず、図１１１の（１）のタイミングで、スイッチトランジスタＳＷのゲートに印加される電圧ＶＳＷに正電圧を印加することで、スイッチトランジスタＳＷをオン状態とする。続いて、第２電極８２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。このとき、第１電極８１１に印加される電圧Ｖｃは、０Ｖであるため、光検出装置８００の第１領域８１０及び第２領域８２０の間には、逆バイアスが印加されることになる。なお、制御ゲートＣＧに印加される電圧Ｖｃｏｎは、負電圧（例えば、－１Ｖ）に設定する。 As shown in FIGS. 111 and 113A, first, at the timing of (1) in FIG. 111, a positive voltage is applied to the voltage V SW applied to the gate of the switch transistor SW to turn on the switch transistor SW. To do. Subsequently, the voltage Va applied to the second electrode 821 is set to a negative voltage (for example, -1V). At this time, since the voltage Vc applied to the first electrode 811 is 0 V, a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800. The voltage V con applied to the control gate CG is set to a negative voltage (for example, -1V).
　ここで、図１１１、図１１２、及び図１１３Ｂに示すように、図１１１の（２）のタイミングで、レーザダイオード又はＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）などの光源ＬＤにパルス状の負電圧Ｖｌｉｇｈｔを印加することで、対象物にパルス光を照射する。同時に、第２電極８２１に印加される電圧Ｖａを正電圧（例えば、＋１Ｖ）とすることで、光検出装置８００の第１領域８１０及び第２領域８２０の間に順バイアスを印加する。また、制御ゲートＣＧに印加される電圧Ｖｃｏｎを正電圧（例えば、＋１Ｖ）に設定する。 Here, as shown in FIGS. 111, 112, and 113B, a pulsed negative voltage V light is applied to the light source LD such as a laser diode or an LED (Light Emitting Diode) at the timing of (2) in FIG. 111. By doing so, the object is irradiated with pulsed light. At the same time, by setting the voltage Va applied to the second electrode 821 to a positive voltage (for example, + 1V), a forward bias is applied between the first region 810 and the second region 820 of the photodetector 800. Further, the voltage V con applied to the control gate CG is set to a positive voltage (for example, + 1V).
　その後、対象物にて反射されたパルス光が光検出装置８００に入射し、第２電極８２１から出力される電流値が（２）のタイミングから遅延して増加する。したがって、光検出装置８００は、光源ＬＤの発光タイミングｔ２と、光検出の遅延時間ｔ１との差を算出することで、対象物までの距離を算出することができる。 After that, the pulsed light reflected by the object is incident on the photodetector 800, and the current value output from the second electrode 821 is delayed from the timing of (2) and increases. Therefore, the photodetector 800 can calculate the distance to the object by calculating the difference between the light emission timing t2 of the light source LD and the light detection delay time t1.
　さらに、図１１１及び図１１３Ｃに示すように、図１１１の（３）のタイミングで第２電極８２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。これにより、光検出装置８００の第１領域８１０及び第２領域８２０の間には逆バイアスが印加されるため、光検出装置８００の状態がリセットされる。なお、制御ゲートＣＧに印加される電圧Ｖｃｏｎも同様に負電圧（例えば、－１Ｖ）に設定してもよい。 Further, as shown in FIGS. 111 and 113C, the voltage Va applied to the second electrode 821 at the timing of (3) in FIG. 111 is set to a negative voltage (for example, -1V). As a result, a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800, so that the state of the photodetector 800 is reset. The voltage V con applied to the control gate CG may also be set to a negative voltage (for example, -1V).
　以上の動作を（１）から（３）までの時間を１フレームとして繰り返すことで、光検出装置８００は、対象物までの距離を１フレームごとに検出することができる。 By repeating the above operation with the time from (1) to (3) as one frame, the photodetector 800 can detect the distance to the object for each frame.
　一方、ＰＤ側の画素回路である転送ゲートＴＲＧのゲートへの印加電圧ＶＴＲＧ、及びリセットトランジスタＲＳＴのゲートへの印加電圧ＶＲＳＴは、１フレーム全体を通して０Ｖである。また、フローティングディフュージョンＦＤに電気的に接続された取出電極８９３の電圧は、１フレーム全体を通して変化しない。 On the other hand, the voltage V TRG applied to the gate of the transfer gate TRG, which is the pixel circuit on the PD side, and the voltage V RST applied to the gate of the reset transistor RST are 0 V throughout one frame. Also, the voltage of the take-out electrode 893 electrically connected to the floating diffusion FD does not change throughout the entire frame.
　さらに、図１１４～図１１５Ｅを参照して、本実施形態に係る光検出装置８００のＰＤとしての動作例について説明する。 Further, an operation example of the photodetector 800 according to the present embodiment as a PD will be described with reference to FIGS. 114 to 115E.
　図１１４は、本実施形態に係る光検出装置８００のＰＤ動作の一例を示すタイミングチャート図である。図１１５Ａは、図１１４の（１）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１１５Ｂは、図１１４の（２）のタイミングにおける光検出装置８００の状態を説明する縦断面図である。図１１５Ｃは、図１１４の（３）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１１５Ｄは、図１１４の（４）のタイミングにおける光検出装置８００の状態を説明する縦断面図である。図１１５Ｅは、図１１４の（５）のタイミングにおける光検出装置８００の状態を説明する縦断面図である。 FIG. 114 is a timing chart showing an example of PD operation of the photodetector 800 according to the present embodiment. FIG. 115A is a vertical sectional view illustrating the state of the photodetector 800 at the timing of FIG. 114 (1), and FIG. 115B describes the state of the photodetector 800 at the timing of FIG. 114 (2). It is a vertical sectional view. FIG. 115C is a vertical cross-sectional view illustrating the state of the photodetector 800 at the timing of FIG. 114 (3), and FIG. 115D describes the state of the photodetector 800 at the timing of FIG. 114 (4). It is a vertical sectional view. FIG. 115E is a vertical cross-sectional view illustrating a state of the photodetector 800 at the timing of FIG. 114 (5).
　図１１４及び図１１５Ａに示すように、まず、図１１４の（１）のタイミングで、スイッチトランジスタＳＷのゲートに印加される電圧ＶＳＷを０Ｖとすることで、スイッチトランジスタＳＷをオフ状態とし、第２電極８２１に印加される電圧Ｖａを０Ｖとする。また、リセットトランジスタＲＳＴのゲートにパルス状の電圧ＶＲＳＴ（例えば、＋１Ｖ）を印加することで、フローティングディフュージョンＦＤに蓄積された電荷を電源Ｖｄに排出し、フローティングディフュージョンＦＤの状態をリセットする。 As shown in FIGS. 114 and 115A, first, at the timing of (1) in FIG. 114, the voltage V SW applied to the gate of the switch transistor SW is set to 0 V, so that the switch transistor SW is turned off. The voltage Va applied to the two electrodes 821 is 0V. Further, by applying a pulsed voltage VRST (for example, + 1V) to the gate of the reset transistor RST, the electric charge accumulated in the floating diffusion FD is discharged to the power supply Vd, and the state of the floating diffusion FD is reset.
　その後、図１１５Ｂに示すように、転送トランジスタＴＲＧのゲートにパルス状の電圧ＶＴＲＧ（例えば、－３Ｖ）を印加することで、第２領域８２０に存在する電荷をフローティングディフュージョンＦＤに転送し、第２領域８２０の状態をリセットする。これにより、図１１４の（２）のタイミングで、光検出装置８００は、入射光の受光を開始可能な状態となる。 Then, as shown in FIG. 115B, by applying a pulsed voltage V TRG (for example, -3V) to the gate of the transfer transistor TRG, the electric charge existing in the second region 820 is transferred to the floating diffusion FD, and the first 2 Reset the state of region 820. As a result, at the timing of (2) in FIG. 114, the photodetector 800 is ready to start receiving the incident light.
　続いて、図１１４及び図１１５Ｃに示すように、光検出装置８００は、第３領域８３０に入射した光を光電変換し、光電変換した電荷を第２領域８２０に蓄積する。 Subsequently, as shown in FIGS. 114 and 115C, the photodetector 800 photoelectrically converts the light incident on the third region 830 and stores the photoelectrically converted charge in the second region 820.
　図１１４の（１）のタイミングから所定の時間が経過した後、図１１４及び図１１５Ｄに示すように、図１１４の（４）のタイミングで、リセットトランジスタＲＳＴのゲートにパルス状の電圧ＶＲＳＴ（例えば、＋１Ｖ）を印加することで、フローティングディフュージョンＦＤに蓄積された電荷を電源Ｖｄに排出し、フローティングディフュージョンＦＤの状態をリセットする。 After a predetermined time has elapsed from the timing of (1) in FIG. 114, as shown in FIGS. 114 and 115D, at the timing of (4) of FIG. 114, a pulsed voltage VRST ( For example, by applying + 1V), the electric charge accumulated in the floating diffusion FD is discharged to the power supply Vd, and the state of the floating diffusion FD is reset.
　図１１５Ｅに示すように、その後、転送トランジスタＴＲＧのゲートにパルス状の電圧ＶＴＲＧ（例えば、－３Ｖ）を印加することで、第２領域８２０に蓄積された電荷をフローティングディフュージョンＦＤに転送し、取出電極８９３より信号電荷を読み出す。これにより、光検出装置８００は、図１１４の（５）のタイミングにて、図１１４の（２）のタイミングと同じ状態となるため、再度、入射光の受光を開始することができる。 As shown in FIG. 115E, the charge accumulated in the second region 820 is then transferred to the floating diffusion FD by applying a pulsed voltage V TRG (for example, -3V) to the gate of the transfer transistor TRG. The signal charge is read out from the take-out electrode 893. As a result, the photodetector 800 is in the same state as the timing of FIG. 114 (2) at the timing of FIG. 114 (5), so that it is possible to start receiving the incident light again.
　以上の動作を（１）から（４）までの時間を１フレームとして繰り返すことで、光検出装置８００は、１フレームごとに受光量に応じた電荷を電気信号に変換し、画像信号として出力することができる。 By repeating the above operation with the time from (1) to (4) as one frame, the photodetector 800 converts the electric charge according to the amount of received light into an electric signal for each frame and outputs it as an image signal. be able to.
　（画素アレイの回路構造）
　さらに、図１１６を参照して、複数の画素が行列状に配列された画素アレイとして本実施形態に係る光検出装置８００を構成した場合の回路構成の一例について説明する。図１１６は、本実施形態に係る光検出装置８００を画素アレイとした場合の機能構成を示すブロック図である。 (Pixel array circuit structure)
Further, with reference to FIG. 116, an example of a circuit configuration in the case where the photodetector 800 according to the present embodiment is configured as a pixel array in which a plurality of pixels are arranged in a matrix will be described. FIG. 116 is a block diagram showing a functional configuration when the photodetector 800 according to the present embodiment is a pixel array.
　図１１６に示すように、各画素の光電変換部ＤＰＤ／ＰＤには、ＤＰＤ制御回路８０１、ＤＰＤ信号検出回路８０３、ＰＤ制御回路８０２、及びＰＤ信号検出回路８０４が接続される。 As shown in FIG. 116, a DPD control circuit 801 and a DPD signal detection circuit 803, a PD control circuit 802, and a PD signal detection circuit 804 are connected to the photoelectric conversion unit DPD / PD of each pixel.
　各画素のＤＰＤ制御回路８０１及びＤＰＤ信号検出回路８０３は、ＤＰＤ水平制御部８２１０、ＤＰＤ信号処理部８２２０、及び垂直制御部８３００と接続される。また、各画素のＰＤ制御回路８０２及びＰＤ信号検出回路８０４は、ＰＤ水平制御部８１１０、ＰＤ信号処理部８１２０、及び垂直制御部８３００と接続される。また、各画素は、光電変換部ＤＰＤ／ＰＤのＤＰＤ動作又はＰＤ動作の切り替えを行うＤＰＤ／ＰＤ切替制御部８４００と接続される。 The DPD control circuit 801 and the DPD signal detection circuit 803 of each pixel are connected to the DPD horizontal control unit 8210, the DPD signal processing unit 8220, and the vertical control unit 8300. Further, the PD control circuit 802 and the PD signal detection circuit 804 of each pixel are connected to the PD horizontal control unit 8110, the PD signal processing unit 8120, and the vertical control unit 8300. Further, each pixel is connected to the DPD / PD switching control unit 8400 that switches the DPD operation or the PD operation of the photoelectric conversion unit DPD / PD.
　ＤＰＤ／ＰＤ切替制御部８４００は、ＤＰＤ水平制御部８２１０、ＰＤ水平制御部８１１０、及び各画素と接続される。ＤＰＤ／ＰＤ切替制御部８４００は、ＤＰＤ／ＰＤ切替信号を出力することで、各画素のＤＰＤ／ＰＤ動作を切り替える。 The DPD / PD switching control unit 8400 is connected to the DPD horizontal control unit 8210, the PD horizontal control unit 8110, and each pixel. The DPD / PD switching control unit 8400 switches the DPD / PD operation of each pixel by outputting the DPD / PD switching signal.
　なお、ＤＰＤ／ＰＤ動作の切り替えは、イメージング又は測距などの用途に応じて、全画素一括で行われてもよく、画素アレイの所定の画素ごとに行われてもよい。また、ＤＰＤ／ＰＤ動作の切り替えは、時間を区切って行われてもよく、フレームごとに行われてもよい。 Note that the DPD / PD operation switching may be performed for all pixels at once or for each predetermined pixel of the pixel array, depending on the application such as imaging or distance measurement. Further, the switching of the DPD / PD operation may be performed by dividing the time, or may be performed for each frame.
　垂直制御部８３００は、ＤＰＤ水平制御部８２１０及びＰＤ水平制御部８１１０に接続され、光電変換部ＤＰＤ／ＰＤにてＤＰＤ動作及びＰＤ動作が行われた際に、ＤＰＤ水平制御部８２１０及びＰＤ水平制御部８１１０に行ごとに読み出し信号を出力する。 The vertical control unit 8300 is connected to the DPD horizontal control unit 8210 and the PD horizontal control unit 8110, and when the DPD operation and the PD operation are performed by the photoelectric conversion unit DPD / PD, the DPD horizontal control unit 8210 and the PD horizontal control unit 8300 are controlled. A read signal is output to unit 8110 line by line.
　ＤＰＤ水平制御部８２１０は、行ごとの読み出し信号が入力された場合、列ごとに各画素のＤＰＤ信号を読み出し、読み出したＤＰＤ信号をＤＰＤ信号処理部８２２０に出力する。 When the read signal for each row is input, the DPD horizontal control unit 8210 reads the DPD signal of each pixel for each column and outputs the read DPD signal to the DPD signal processing unit 8220.
　ＤＰＤ信号処理部８２２０は、入力されたＤＰＤ信号を信号処理した後、信号処理されたＤＰＤ信号をＴｏＦデータとして出力する。 The DPD signal processing unit 8220 processes the input DPD signal and then outputs the processed DPD signal as ToF data.
　ＰＤ水平制御部８１１０は、行ごとの読み出し信号が入力された場合、列ごとに各画素のＰＤ信号を読み出し、読み出したＰＤ信号をＰＤ信号処理部８１２０に出力する。 When the read signal for each row is input, the PD horizontal control unit 8110 reads the PD signal of each pixel for each column and outputs the read PD signal to the PD signal processing unit 8120.
　ＰＤ信号処理部８１２０は、入力されたＰＤ信号を信号処理した後、信号処理されたＰＤ信号を画像データとして出力する。 The PD signal processing unit 8120 processes the input PD signal and then outputs the processed PD signal as image data.
　ＴｏＦ光源制御部８５００は、垂直制御部８３００及びＤＰＤ信号処理部８２２０と接続され、ＴｏＦ動作の際の発光する光源ＬＤの発光タイミングを制御する。ＴｏＦ光源制御部８５００は、光源ＬＤの発光のタイミング信号を垂直制御部８３００及びＤＰＤ信号処理部８２２０に出力することで、ＤＰＤ信号の信号処理、又はＤＰＤ信号の読み出しを制御してもよい。 The ToF light source control unit 8500 is connected to the vertical control unit 8300 and the DPD signal processing unit 8220, and controls the light emission timing of the light source LD that emits light during the ToF operation. The ToF light source control unit 8500 may control the signal processing of the DPD signal or the reading of the DPD signal by outputting the light emission timing signal of the light source LD to the vertical control unit 8300 and the DPD signal processing unit 8220.
　（バリエーション）
　続いて、図１１７Ａ～図１２７Ｃを参照して、本実施形態に係る光検出装置８００の構造のバリエーションについて説明する。 (variation)
Subsequently, with reference to FIGS. 117A to 127C, variations in the structure of the photodetector 800 according to the present embodiment will be described.
　（第１のバリエーション）
　図１１７Ａは、第１のバリエーションに係る光検出装置８００Ａの構造を示す第２面側から見た平面図である。図１１７Ｂは、図１１７ＡのＡ－ＡＡ切断面における光検出装置８００Ａの構造を示す縦断面図である。図１１７Ｃは、図１１７ＡのＢ－ＢＢ切断面における光検出装置８００Ａの構造を示す縦断面図である。 (First variation)
FIG. 117A is a plan view of the photodetector 800A according to the first variation as viewed from the second surface side. FIG. 117B is a vertical cross-sectional view showing the structure of the photodetector 800A on the AA cut surface of FIG. 117A. FIG. 117C is a vertical cross-sectional view showing the structure of the photodetector 800A on the B-BB cut surface of FIG. 117A.
　図１１７Ａ～図１１７Ｃに示すように、光検出装置８００Ａは、図１０８Ａ～図１０８Ｃにて説明した光検出装置８００に対して、第１導電型領域８９５、オーバーフローゲートＯＦＧ、オーバーフロードレインＯＦＤ、及び排出電極８９７をさらに備える点が異なる。 As shown in FIGS. 117A to 117C, the photodetector 800A has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and discharge with respect to the photodetector 800 described with reference to FIGS. 108A to 108C. The difference is that the electrode 897 is further provided.
　第１導電型領域８９５は、半導体基板の第２面側に設けられた第１導電型の領域（例えば、Ｎ層）である。第１導電型領域８９５は、例えば、第１領域８１０よりも導電型不純物の濃度が低く、第３領域８３０よりも導電型不純物の濃度が高くなるように設けられる。第１導電型領域８９５は、第１導電型領域８９１の延在方向と反対方向に第２領域８２０から延在して設けられてもよい。 The first conductive type region 895 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate. The first conductive region 895 is provided so that, for example, the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830. The first conductive type region 895 may be provided extending from the second region 820 in a direction opposite to the extending direction of the first conductive type region 891.
　オーバーフロードレインＯＦＤは、第２領域８２０よりも導電型不純物の濃度が高い第２導電型の領域（例えば、Ｐ＋＋層）であり、半導体基板の第２面側に設けられる。オーバーフロードレインＯＦＤは、第２領域８２０から延在する第１導電型領域８９５の端部側に設けられてもよい。 The overflow drain OFD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate. The overflow drain OFD may be provided on the end side of the first conductive type region 895 extending from the second region 820.
　オーバーフローゲートＯＦＧは、半導体基板の第２面の上にゲート絶縁膜（図示せず）を介して設けられるゲート電極である。オーバーフローゲートＯＦＧは、第２領域８２０と、オーバーフロードレインＯＦＤとの間に設けられ、第２領域８２０からオーバーフロードレインＯＦＤへの電荷の排出を制御する。 The overflow gate OFG is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film (not shown). The overflow gate OFG is provided between the second region 820 and the overflow drain OFD, and controls the discharge of electric charge from the second region 820 to the overflow drain OFD.
　ここで、第１導電型領域８９５は、オーバーフローゲートＯＦＧの下方の領域、及びオーバーフロードレインＯＦＤが設けられた領域を囲む領域に設けられてもよい。これによれば、第１導電型領域８９５は、第２領域８２０からオーバーフローゲートＯＦＧへ電荷を排出するチャネルとして機能することができる。また、第１導電型領域８９５は、第３領域８３０にて光電変換された電荷がオーバーフロードレインＯＦＤに直接入り込むことを防止することができる。 Here, the first conductive type region 895 may be provided in a region below the overflow gate OFG and a region surrounding the region in which the overflow drain OFD is provided. According to this, the first conductive type region 895 can function as a channel for discharging the electric charge from the second region 820 to the overflow gate OFG. Further, the first conductive type region 895 can prevent the charge photoelectrically converted in the third region 830 from directly entering the overflow drain OFD.
　排出電極８９７は、半導体基板の第１面の上に設けられ、オーバーフロードレインＯＦＤと電気的に接続する。排出電極８９７は、電源に電気的に接続され、オーバーフロードレインＯＦＤに排出された電荷をさらに電源に排出することができる。 The discharge electrode 897 is provided on the first surface of the semiconductor substrate and is electrically connected to the overflow drain OFD. The discharge electrode 897 is electrically connected to the power supply, and the electric charge discharged to the overflow drain OFD can be further discharged to the power supply.
　これによれば、光検出装置８００Ａは、ＰＤ動作時に飽和電荷量を超えて発生した電荷を第２領域８２０からオーバーフロードレインＯＦＤに排出することができる。オーバーフロードレインＯＦＤに排出された電荷は、排出電極８９７を介して電源にさらに排出される。したがって、光検出装置８００Ａは、ＰＤ動作時にブルーミングが発生することを抑制することができる。 According to this, the photodetector 800A can discharge the electric charge generated in excess of the saturated charge amount during the PD operation from the second region 820 to the overflow drain OFD. The electric charge discharged to the overflow drain OFD is further discharged to the power supply via the discharge electrode 897. Therefore, the photodetector 800A can suppress the occurrence of blooming during PD operation.
　第１のバリエーションによれば、光検出装置８００Ａは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the first variation, the photodetector 800A can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（第２のバリエーション）
　図１１８Ａは、第２のバリエーションに係る光検出装置８００Ｂの構造を示す第２面側から見た平面図である。図１１８Ｂは、図１１８ＡのＡ－ＡＡ切断面における光検出装置８００Ｂの構造を示す縦断面図である。図１１８Ｃは、図１１８ＡのＢ－ＢＢ切断面における光検出装置８００Ｂの構造を示す縦断面図である。 (Second variation)
FIG. 118A is a plan view of the photodetector 800B according to the second variation as viewed from the second surface side. FIG. 118B is a vertical cross-sectional view showing the structure of the photodetector 800B on the AA cut surface of FIG. 118A. FIG. 118C is a vertical cross-sectional view showing the structure of the photodetector 800B on the B-BB cut surface of FIG. 118A.
　図１１８Ａ～図１１８Ｃに示すように、光検出装置８００Ｂは、図１０８Ａ～図１０８Ｃにて説明した光検出装置８００に対して、画素領域を画定する画素分離層８５０をさらに備える点が異なる。 As shown in FIGS. 118A to 118C, the photodetector 800B is different from the photodetector 800 described with reference to FIGS. 108A to 108C in that it further includes a pixel separation layer 850 that defines a pixel region.
　画素分離層８５０は、矩形形状の画素領域の外周を囲むように、半導体基板の第２面側から半導体基板の厚み方向に延在して設けられ、隣接する画素同士を電気的に分離する。画素分離層８５０の形成深さは、例えば、第２領域８２０、第１導電型領域８９１、及び画素トランジスタ領域Ｔｒの形成深さよりも深くてもよい。画素分離層８５０は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The pixel separation layer 850 is provided so as to surround the outer periphery of the rectangular pixel region so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and electrically separate adjacent pixels from each other. The formation depth of the pixel separation layer 850 may be deeper than, for example, the formation depth of the second region 820, the first conductive type region 891, and the pixel transistor region Tr. The pixel separation layer 850 may be provided with an insulator such as silicon oxide (SiOx), silicon nitride (SiNx), silicon nitriding (SiON), or a so-called low-k material.
　第２のバリエーションによれば、光検出装置８００Ｂは、画素分離層８５０によって隣接する画素間を電気的に分離することができるため、画素間のクロストークを抑制することができる。 According to the second variation, the photodetector 800B can electrically separate adjacent pixels by the pixel separation layer 850, so that crosstalk between pixels can be suppressed.
　（第３のバリエーション）
　図１１９Ａは、第３のバリエーションに係る光検出装置８００Ｃの構造を示す第２面側から見た平面図である。図１１９Ｂは、図１１９ＡのＡ－ＡＡ切断面における光検出装置８００Ｃの構造を示す縦断面図である。図１１９Ｃは、図１１９ＡのＢ－ＢＢ切断面における光検出装置８００Ｃの構造を示す縦断面図である。 (Third variation)
FIG. 119A is a plan view of the photodetector 800C according to the third variation as viewed from the second surface side. FIG. 119B is a vertical cross-sectional view showing the structure of the photodetector 800C on the AA cut surface of FIG. 119A. FIG. 119C is a vertical cross-sectional view showing the structure of the photodetector 800C on the B-BB cut surface of FIG. 119A.
　図１１９Ａ～図１１９Ｃに示すように、光検出装置８００Ｃは、第２のバリエーションに係る光検出装置８００Ｂに対して、第１導電型領域８９５、オーバーフローゲートＯＦＧ、オーバーフロードレインＯＦＤ、及び排出電極８９７をさらに備える点が異なる。 As shown in FIGS. 119A to 119C, the photodetector 800C provides the first conductive region 895, the overflow gate OFG, the overflow drain OFD, and the discharge electrode 897 with respect to the photodetector 800B according to the second variation. Furthermore, the points to be prepared are different.
　第３のバリエーションによれば、光検出装置８００Ｃは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the third variation, the photodetector 800C can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（第４のバリエーション）
　図１２０Ａは、第４のバリエーションに係る光検出装置８００Ｄの構造を示す第２面側から見た平面図である。図１２０Ｂは、図１２０ＡのＡ－ＡＡ切断面における光検出装置８００Ｄの構造を示す縦断面図である。図１２０Ｃは、図１２０ＡのＢ－ＢＢ切断面における光検出装置８００Ｄの構造を示す縦断面図である。 (Fourth variation)
FIG. 120A is a plan view of the photodetector 800D according to the fourth variation as viewed from the second surface side. FIG. 120B is a vertical cross-sectional view showing the structure of the photodetector 800D on the AA cut surface of FIG. 120A. FIG. 120C is a vertical cross-sectional view showing the structure of the photodetector 800D on the B-BB cut surface of FIG. 120A.
　図１２０Ａ～図１２０Ｃに示すように、光検出装置８００Ｄは、図１１８Ａ～図１１８Ｃにて説明した光検出装置８００Ｂに対して、画素分離層８５０の内部に金属層８５２をさらに備える点が異なる。 As shown in FIGS. 120A to 120C, the photodetector 800D is different from the photodetector 800B described in FIGS. 118A to 118C in that the metal layer 852 is further provided inside the pixel separation layer 850.
　金属層８５２は、遮光性を有する金属にて画素分離層８５０の内部に設けられる。具体的には、金属層８５２は、半導体基板の第２面側から半導体基板の厚み方向に延在して設けられ、かつ画素分離層８５０にて側面及び底面を覆われて設けられる。金属層８５２は、遮光性を有するため、光検出装置８００Ｄに斜め方向から入射する光が隣接する画素に進入することを防止することができる。金属層８５２は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、又はこれらの合金にて設けられてもよい。 The metal layer 852 is made of a light-shielding metal and is provided inside the pixel separation layer 850. Specifically, the metal layer 852 is provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and the side surface and the bottom surface are covered with the pixel separation layer 850. Since the metal layer 852 has a light-shielding property, it is possible to prevent light incident on the photodetector 800D from an oblique direction from entering adjacent pixels. The metal layer 852 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
　第４のバリエーションによれば、光検出装置８００Ｄは、金属層８５２によって画素間での光の進入を防止することができるため、画素間のクロストークをさらに抑制することができる。 According to the fourth variation, the photodetector 800D can prevent light from entering between pixels by the metal layer 852, so that crosstalk between pixels can be further suppressed.
　（第５のバリエーション）
　図１２１Ａは、第５のバリエーションに係る光検出装置８００Ｅの構造を示す第２面側から見た平面図である。図１２１Ｂは、図１２１ＡのＡ－ＡＡ切断面における光検出装置８００Ｅの構造を示す縦断面図である。図１２１Ｃは、図１２１ＡのＢ－ＢＢ切断面における光検出装置８００Ｅの構造を示す縦断面図である。 (Fifth variation)
FIG. 121A is a plan view of the photodetector 800E according to the fifth variation as viewed from the second surface side. FIG. 121B is a vertical cross-sectional view showing the structure of the photodetector 800E on the AA cut surface of FIG. 121A. FIG. 121C is a vertical cross-sectional view showing the structure of the photodetector 800E on the B-BB cut surface of FIG. 121A.
　図１２１Ａ～図１２１Ｃに示すように、光検出装置８００Ｅは、第４のバリエーションに係る光検出装置８００Ｄに対して、第１導電型領域８９５、オーバーフローゲートＯＦＧ、オーバーフロードレインＯＦＤ、及び排出電極８９７がさらに設けられる点が異なる。 As shown in FIGS. 121A to 121C, the photodetector 800E has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and an discharge electrode 897 with respect to the photodetector 800D according to the fourth variation. Furthermore, the point that it is provided is different.
　第５のバリエーションによれば、光検出装置８００Ｅは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the fifth variation, the photodetector 800E can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（第６のバリエーション）
　図１２２Ａは、第６のバリエーションに係る光検出装置８００Ｆの構造を示す第２面側から見た平面図である。図１２２Ｂは、図１２２ＡのＡ－ＡＡ切断面における光検出装置８００Ｆの構造を示す縦断面図である。図１２２Ｃは、図１２２ＡのＢ－ＢＢ切断面における光検出装置８００Ｆの構造を示す縦断面図である。 (Sixth variation)
FIG. 122A is a plan view of the photodetector 800F according to the sixth variation as viewed from the second surface side. FIG. 122B is a vertical cross-sectional view showing the structure of the photodetector 800F on the AA cut surface of FIG. 122A. FIG. 122C is a vertical cross-sectional view showing the structure of the photodetector 800F on the B-BB cut surface of FIG. 122A.
　図１２２Ａ～図１２２Ｃに示すように、光検出装置８００Ｆは、図１０８Ａ～図１０８Ｃにて説明した光検出装置８００に対して、制御ゲートＣＧが縦型ゲート構造にて設けられる点が異なる。 As shown in FIGS. 122A to 122C, the photodetector 800F is different from the photodetector 800 described with reference to FIGS. 108A to 108C in that the control gate CG is provided in a vertical gate structure.
　具体的には、制御ゲートＣＧは、掘り込み電極８６５、及びゲート絶縁膜８６３にて構成されてもよい。掘り込み電極８６５は、半導体基板の第２面側から半導体基板の厚み方向に延在するように設けられ、掘り込み電極８６５の側面及び底面にはゲート絶縁膜８６３が設けられてもよい。なお、掘り込み電極８６５は、半導体基板の面内方向では矩形形状にて設けられてもよい。 Specifically, the control gate CG may be composed of a digging electrode 865 and a gate insulating film 863. The digging electrode 865 may be provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and a gate insulating film 863 may be provided on the side surface and the bottom surface of the digging electrode 865. The digging electrode 865 may be provided in a rectangular shape in the in-plane direction of the semiconductor substrate.
　第６のバリエーションによれば、光検出装置８００Ｆは、ＤＰＤ動作時に第２領域８２０に隣接する領域に生じるポテンシャル障壁の制御性をより向上させることができるため、入射光の検出特性をより向上させることができる。 According to the sixth variation, the photodetector 800F can further improve the controllability of the potential barrier generated in the region adjacent to the second region 820 during the DPD operation, and thus further improve the detection characteristics of the incident light. be able to.
　（第７のバリエーション）
　図１２３Ａは、第７のバリエーションに係る光検出装置８００Ｇの構造を示す第２面側から見た平面図である。図１２３Ｂは、図１２３ＡのＡ－ＡＡ切断面における光検出装置８００Ｇの構造を示す縦断面図である。図１２３Ｃは、図１２３ＡのＢ－ＢＢ切断面における光検出装置８００Ｇの構造を示す縦断面図である。 (7th variation)
FIG. 123A is a plan view of the photodetector 800G according to the seventh variation as viewed from the second surface side. FIG. 123B is a vertical cross-sectional view showing the structure of the photodetector 800G on the AA cut surface of FIG. 123A. FIG. 123C is a vertical cross-sectional view showing the structure of the photodetector 800G on the B-BB cut surface of FIG. 123A.
　図１２３Ａ～図１２３Ｃに示すように、光検出装置８００Ｇは、第６のバリエーションに係る光検出装置８００Ｆに対して、第１導電型領域８９５、オーバーフローゲートＯＦＧ、オーバーフロードレインＯＦＤ、及び排出電極８９７がさらに設けられる点が異なる。 As shown in FIGS. 123A to 123C, the photodetector 800G has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and an discharge electrode 897 with respect to the photodetector 800F according to the sixth variation. Furthermore, the point that it is provided is different.
　第７のバリエーションによれば、光検出装置８００Ｇは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the seventh variation, the photodetector 800G can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（第８のバリエーション）
　図１２４Ａは、第８のバリエーションに係る光検出装置８００Ｈの構造を示す第２面側から見た平面図である。図１２４Ｂは、図１２４ＡのＡ－ＡＡ切断面における光検出装置８００Ｈの構造を示す縦断面図である。図１２４Ｃは、図１２４ＡのＢ－ＢＢ切断面における光検出装置８００Ｈの構造を示す縦断面図である。 (8th variation)
FIG. 124A is a plan view of the photodetector 800H according to the eighth variation as viewed from the second surface side. FIG. 124B is a vertical cross-sectional view showing the structure of the photodetector 800H on the AA cut surface of FIG. 124A. FIG. 124C is a vertical cross-sectional view showing the structure of the photodetector 800H on the B-BB cut surface of FIG. 124A.
　図１２４Ａ～図１２４Ｃに示すように、光検出装置８００Ｈは、例えば、第１領域８１０と、第２領域８２０と、第３領域８３０と、第１電極８１１と、ビア８１２と、第１面絶縁層８５１と、画素分離層８５０と、金属層８５２と、第２電極８２１と、制御ゲート８６１と、ゲート絶縁膜８６２と、画素トランジスタ領域Ｔｒと、第１導電型領域８９１と、転送ゲート８９２と、ゲート絶縁膜８９４と、フローティングディフュージョンＦＤと、取出電極８９３とを備える。 As shown in FIGS. 124A to 124C, the light detection device 800H has, for example, a first region 810, a second region 820, a third region 830, a first electrode 811, a via 812, and a first surface insulation. The layer 851, the pixel separation layer 850, the metal layer 852, the second electrode 821, the control gate 861, the gate insulating film 862, the pixel transistor region Tr, the first conductive region 891, and the transfer gate 892. , A gate insulating film 894, a floating diffusion FD, and an extraction electrode 893 are provided.
　第１領域８１０は、半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域８２０は、半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域８３０は、半導体基板の第１領域８１０と第２領域８２０との間に設けられた第３導電型の領域（例えば、ｉ層又はＮ－層）である。 The first region 810 is a first conductive type region (for example, N + layer) provided on the first surface side of the semiconductor substrate. The second region 820 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate. The third region 830 is a third conductive type region (for example, i-layer or N-layer) provided between the first region 810 and the second region 820 of the semiconductor substrate.
　第１電極８１１は、半導体基板の第１面の上に第１面絶縁層８５１を介して設けられ、第１面絶縁層８５１を貫通するビア８１２等を介して第１領域８１０と電気的に接続する。第１電極８１１は、例えば、カソード電極として機能する。第１電極８１１は、画素同士の境界に設けられた画素分離層８５０を跨ぐように設けられ、画素ごとに設けられたビア８１２にて、各画素の第１領域８１０と電気的に接続する。これにより、第１電極８１１は、画素分離層８５０にて電気的に離隔された各画素の第１領域８１０に共通の電位を供給することができる。 The first electrode 811 is provided on the first surface of the semiconductor substrate via the first surface insulating layer 851, and is electrically connected to the first region 810 via a via 812 or the like penetrating the first surface insulating layer 851. Connecting. The first electrode 811 functions as, for example, a cathode electrode. The first electrode 811 is provided so as to straddle the pixel separation layer 850 provided at the boundary between pixels, and is electrically connected to the first region 810 of each pixel by a via 812 provided for each pixel. As a result, the first electrode 811 can supply a common potential to the first region 810 of each pixel electrically separated by the pixel separation layer 850.
　画素分離層８５０は、半導体基板を厚み方向に貫通して設けられ、半導体基板の面内方向に複数設けられた画素の各々を互いに電気的に離隔する。画素分離層８５０は、例えば、半導体基板の面内方向に行列状に配列された各画素の境界に沿って、格子状に設けられてもよい。 The pixel separation layer 850 is provided so as to penetrate the semiconductor substrate in the thickness direction, and electrically separates each of a plurality of pixels provided in the in-plane direction of the semiconductor substrate from each other. The pixel separation layer 850 may be provided, for example, in a grid pattern along the boundary of each pixel arranged in a matrix in the in-plane direction of the semiconductor substrate.
　金属層８５２は、遮光性を有する金属にて画素分離層８５０の内部に設けられる。具体的には、金属層８５２は、半導体基板の第２面側から半導体基板の厚み方向に延在して設けられ、かつ画素分離層８５０にて側面及び底面を覆われて設けられる。金属層８５２は、斜め方向から入射する光が隣接する画素に進入することを防止することができる。金属層８５２は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、又はこれらの合金にて設けられてもよい。 The metal layer 852 is made of a light-shielding metal and is provided inside the pixel separation layer 850. Specifically, the metal layer 852 is provided so as to extend from the second surface side of the semiconductor substrate in the thickness direction of the semiconductor substrate, and the side surface and the bottom surface are covered with the pixel separation layer 850. The metal layer 852 can prevent light incident from an oblique direction from entering adjacent pixels. The metal layer 852 may be provided with, for example, a metal such as aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or tantalum (Ta), or an alloy thereof.
　第２電極８２１は、半導体基板の第１面と反対側の第２面の上に設けられ、第２領域８２０と電気的に接続する。第２電極８２１は、例えば、アノード電極として機能する。 The second electrode 821 is provided on the second surface opposite to the first surface of the semiconductor substrate, and is electrically connected to the second region 820. The second electrode 821 functions as, for example, an anode electrode.
　制御ゲート８６１は、半導体基板の第２面の上にゲート絶縁膜８６２を介して設けられるゲート電極である。制御ゲート８６１は、電圧印加によって、第３領域８３０におけるポテンシャル障壁を制御することができる。 The control gate 861 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 862. The control gate 861 can control the potential barrier in the third region 830 by applying a voltage.
　第１導電型領域８９１は、半導体基板の第２面側に設けられた第１導電型の領域（例えば、Ｎ層）である。第１導電型領域８９１は、例えば、第１領域８１０よりも導電型不純物の濃度が低く、第３領域８３０よりも導電型不純物の濃度が高くなるように設けられる。第１導電型領域８９１は、第２領域８２０から一方向に延在して設けられる。 The first conductive type region 891 is a first conductive type region (for example, N layer) provided on the second surface side of the semiconductor substrate. The first conductive region 891 is provided, for example, so that the concentration of the conductive impurities is lower than that of the first region 810 and the concentration of the conductive impurities is higher than that of the third region 830. The first conductive type region 891 is provided so as to extend in one direction from the second region 820.
　フローティングディフュージョンＦＤは、第２領域８２０よりも導電型不純物の濃度が高い第２導電型の領域（例えば、Ｐ＋＋層）であり、半導体基板の第２面側に設けられる。フローティングディフュージョンＦＤは、第２領域８２０から延在する第１導電型領域８９１の端部側にて第１導電型領域８９１の内側に設けられてもよい。 The floating diffusion FD is a second conductive type region (for example, P ++ layer) having a higher concentration of conductive type impurities than the second region 820, and is provided on the second surface side of the semiconductor substrate. The floating diffusion FD may be provided inside the first conductive type region 891 on the end side of the first conductive type region 891 extending from the second region 820.
　転送ゲート８９２は、半導体基板の第２面の上にゲート絶縁膜８９４を介して設けられるゲート電極である。転送ゲート８９２は、第２領域８２０と、フローティングディフュージョンＦＤとの間の第１導電型領域８９１の上に設けられ、電圧印加によって第２領域８２０からフローティングディフュージョンＦＤへ電荷を転送することができる。 The transfer gate 892 is a gate electrode provided on the second surface of the semiconductor substrate via the gate insulating film 894. The transfer gate 892 is provided on the first conductive region 891 between the second region 820 and the floating diffusion FD, and can transfer charges from the second region 820 to the floating diffusion FD by applying a voltage.
　取出電極８９３は、半導体基板の第１面の上に設けられ、フローティングディフュージョンＦＤと電気的に接続する。取出電極８９３は、フローティングディフュージョンＦＤに蓄積された電荷を画素回路等に出力することができる。 The take-out electrode 893 is provided on the first surface of the semiconductor substrate and is electrically connected to the floating diffusion FD. The take-out electrode 893 can output the electric charge accumulated in the floating diffusion FD to a pixel circuit or the like.
　画素トランジスタ領域Ｔｒは、画素回路に含まれる画素トランジスタの少なくともいずれか１つ以上が設けられる領域である。 The pixel transistor region Tr is an region in which at least one or more of the pixel transistors included in the pixel circuit are provided.
　第１電極８１１、ビア８１２、第２電極８２１、制御ゲート８６１、転送ゲート８９２、及び取出電極８９３は、例えば、アルミニウム（Ａｌ）、銅（Ｃｕ）、タングステン（Ｗ）、チタン（Ｔｉ）、若しくはタンタル（Ｔａ）などの金属、ポリシリコン（ｐｏｌｙ－Ｓｉ）、又はその他導電材料にて設けられてもよい。第１面絶縁層８５１、画素分離層８５０、及びゲート絶縁膜８６２、８９４は、酸化シリコン（ＳｉＯｘ）、窒化シリコン（ＳｉＮｘ）、酸窒化シリコン（ＳｉＯＮ）、又はいわゆるｌｏｗ－ｋ材料などの絶縁体にて設けられてもよい。 The first electrode 811, via 812, second electrode 821, control gate 861, transfer gate 892, and take-out electrode 893 may be, for example, aluminum (Al), copper (Cu), tungsten (W), titanium (Ti), or It may be provided by a metal such as tantalum (Ta), polysilicon (poly-Si), or other conductive material. The first surface insulating layer 851, the pixel separation layer 850, and the gate insulating films 862 and 894 are made of silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiON), or a so-called low-k material. It may be provided with an insulator.
　第８のバリエーションによれば、光検出装置８００Ｈは、いわゆる裏面照射型構造で構成される。これにより、光検出装置８００Ｈは、光の検出効率を向上させることができる。また、光検出装置８００Ｈは、画素分離層８５０及び金属層８５２を備えることで、画素間での分離性、及び画素間での光学的なクロストーク特性を向上させることができる。 According to the eighth variation, the photodetector 800H has a so-called back-illuminated structure. As a result, the photodetector 800H can improve the light detection efficiency. Further, the photodetector 800H can improve the separability between pixels and the optical crosstalk characteristics between pixels by providing the pixel separation layer 850 and the metal layer 852.
　（第９のバリエーション）
　図１２５Ａは、第９のバリエーションに係る光検出装置８００Ｉの構造を示す第２面側から見た平面図である。図１２５Ｂは、図１２５ＡのＡ－ＡＡ切断面における光検出装置８００Ｉの構造を示す縦断面図である。図１２５Ｃは、図１２５ＡのＢ－ＢＢ切断面における光検出装置８００Ｉの構造を示す縦断面図である。 (9th variation)
FIG. 125A is a plan view of the photodetector 800I according to the ninth variation as viewed from the second surface side. FIG. 125B is a vertical cross-sectional view showing the structure of the photodetector 800I on the AA cut surface of FIG. 125A. FIG. 125C is a vertical cross-sectional view showing the structure of the photodetector 800I on the B-BB cut surface of FIG. 125A.
　図１２５Ａ～図１２５Ｃに示すように、光検出装置８００Ｉは、第８のバリエーションに係る光検出装置８００Ｈに対して、第１導電型領域８９５、オーバーフローゲート８９６、ゲート絶縁膜８９８、オーバーフロードレインＯＦＤ、及び排出電極８９７がさらに設けられる点が異なる。 As shown in FIGS. 125A to 125C, the photodetector 800I has a first conductive region 895, an overflow gate 896, a gate insulating film 898, and an overflow drain OFD, with respect to the photodetector 800H according to the eighth variation. And the discharge electrode 897 is further provided.
　第９のバリエーションによれば、光検出装置８００Ｉは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the ninth variation, the photodetector 800I can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（第１０のバリエーション）
　図１２６Ａは、第１０のバリエーションに係る光検出装置８００Ｊの構造を示す第２面側から見た平面図である。図１２６Ｂは、図１２６ＡのＡ－ＡＡ切断面における光検出装置８００Ｊの構造を示す縦断面図である。図１２６Ｃは、図１２６ＡのＢ－ＢＢ切断面における光検出装置８００Ｊの構造を示す縦断面図である。 (10th variation)
FIG. 126A is a plan view seen from the second surface side showing the structure of the photodetector 800J according to the tenth variation. FIG. 126B is a vertical cross-sectional view showing the structure of the photodetector 800J on the AA cut surface of FIG. 126A. FIG. 126C is a vertical cross-sectional view showing the structure of the photodetector 800J on the B-BB cut surface of FIG. 126A.
　図１２６Ａ～図１２６Ｃに示すように、光検出装置８００Ｊは、第８のバリエーションに係る光検出装置８００Ｈに対して、第１領域８１０が画素分離層８５０の内部に設けられた側壁電極８５３にて電気的に接続されており、半導体基板の第１面の上には、第１面絶縁層８５１のみが設けられる点が異なる。 As shown in FIGS. 126A to 126C, the photodetector 800J has a side wall electrode 853 in which the first region 810 is provided inside the pixel separation layer 850 with respect to the photodetector 800H according to the eighth variation. The difference is that they are electrically connected and only the first surface insulating layer 851 is provided on the first surface of the semiconductor substrate.
　具体的には、側壁電極８５３は、半導体基板の厚み方向で段差を有するように設けられる。第１領域８１０は、半導体基板の第１面、及び画素分離層８５０の側面に沿って、矩形形状の１辺が開口した形状にて設けられる。これにより、側壁電極８５３は、半導体基板の厚み方向に形成された段差の底面にて第１領域８１０と電気的に接続することができる。 Specifically, the side wall electrode 853 is provided so as to have a step in the thickness direction of the semiconductor substrate. The first region 810 is provided in a shape in which one side of a rectangular shape is open along the first surface of the semiconductor substrate and the side surface of the pixel separation layer 850. As a result, the side wall electrode 853 can be electrically connected to the first region 810 at the bottom surface of the step formed in the thickness direction of the semiconductor substrate.
　第１０のバリエーションによれば、光検出装置８００Ｊは、半導体基板の第１面の上に電極又は配線を設けずとも第１領域８１０と電気的に接続することができるため、開口率をより高めることができる。したがって、光検出装置８００Ｊは、光の検出効率をさらに向上させることができる。 According to the tenth variation, the photodetector 800J can be electrically connected to the first region 810 without providing an electrode or wiring on the first surface of the semiconductor substrate, so that the aperture ratio is further increased. be able to. Therefore, the photodetector 800J can further improve the light detection efficiency.
　（第１１のバリエーション）
　図１２７Ａは、第１１のバリエーションに係る光検出装置８００Ｋの構造を示す第２面側から見た平面図である。図１２７Ｂは、図１２７ＡのＡ－ＡＡ切断面における光検出装置８００Ｋの構造を示す縦断面図である。図１２７Ｃは、図１２７ＡのＢ－ＢＢ切断面における光検出装置８００Ｋの構造を示す縦断面図である。 (11th variation)
FIG. 127A is a plan view seen from the second surface side showing the structure of the photodetector 800K according to the eleventh variation. FIG. 127B is a vertical cross-sectional view showing the structure of the photodetector 800K on the AA cut surface of FIG. 127A. FIG. 127C is a vertical cross-sectional view showing the structure of the photodetector 800K on the B-BB cut surface of FIG. 127A.
　図１２７Ａ～図１２７Ｃに示すように、光検出装置８００Ｋは、第１０のバリエーションに係る光検出装置８００Ｊに対して、第１導電型領域８９５、オーバーフローゲートＯＦＧ、オーバーフロードレインＯＦＤ、及び排出電極８９７がさらに設けられる点が異なる。 As shown in FIGS. 127A to 127C, the photodetector 800K has a first conductive region 895, an overflow gate OFG, an overflow drain OFD, and a discharge electrode 897 with respect to the photodetector 800J according to the tenth variation. Furthermore, the point that it is provided is different.
　第１１のバリエーションによれば、光検出装置８００Ｋは、オーバーフローゲートＯＦＧ、及びオーバーフロードレインＯＦＤをさらに備えることで、ＰＤ動作時のブルーミングを抑制することができる。 According to the eleventh variation, the photodetector 800K can suppress blooming during PD operation by further including an overflow gate OFG and an overflow drain OFD.
　（画素アレイの動作例）
　ここで、図１２８～図１３０を参照して、本実施形態に係る光検出装置８００を複数の画素が行列状に配列された画素アレイとして構成した際の動作例について説明する。図１２８は、複数の画素が行列状に配列された画素アレイの平面構成の一例を示す模式図である。図１２９は、本実施形態に係る光検出装置８００のＤＰＤ動作とＰＤ動作との切り替えを説明する概念図である。図１３０は、本実施形態に係る光検出装置８００のＤＰＤ動作とＰＤ動作との切り替えの流れの一例を示すフローチャート図である。 (Example of pixel array operation)
Here, an example of operation when the photodetector 800 according to the present embodiment is configured as a pixel array in which a plurality of pixels are arranged in a matrix will be described with reference to FIGS. 128 to 130. FIG. 128 is a schematic diagram showing an example of a planar configuration of a pixel array in which a plurality of pixels are arranged in a matrix. FIG. 129 is a conceptual diagram illustrating switching between the DPD operation and the PD operation of the photodetector 800 according to the present embodiment. FIG. 130 is a flowchart showing an example of a flow of switching between the DPD operation and the PD operation of the photodetector 800 according to the present embodiment.
　図１２８に示すように、本実施形態に係る光検出装置８００は、画素アレイ内に、ＤＰＤ動作によってＴｏＦ情報を取得するＴｏＦ画素ＰＴｏＦと、ＰＤ動作によってイメージング情報を取得するイメージング画素Ｐｉｍｇとをそれぞれ含んでいてもよい。例えば、ＴｏＦ画素ＰＴｏＦは、互いに所定の間隔を空けて画素アレイ内に周期的に配置されてもよい。 As shown in FIG. 128, the photodetector 800 according to the present embodiment includes a ToF pixel P ToF that acquires ToF information by a DPD operation and an imaging pixel Pimg that acquires imaging information by a PD operation in a pixel array. May be included respectively. For example, the ToF pixels P ToF may be periodically arranged in the pixel array at predetermined intervals from each other.
　このような場合、ＴｏＦ画素ＰＴｏＦ、及びイメージング画素Ｐｉｍｇは、別の機能を奏する画素としてあらかじめ画素アレイ内に作り込まれていてもよい。または、画素アレイ内の各画素は、ＴｏＦ画素ＰＴｏＦとして動作するか、又はイメージング画素Ｐｉｍｇとして動作するかを選択的に切り替えられてもよい。 In such a case, ToF pixel P ToF, and imaging pixel P img may be built in advance pixel array as a pixel to achieve the different functions. Alternatively, each pixel in the pixel array may be selectively switched between operating as a ToF pixel P ToF or operating as an imaging pixel Pimg .
　または、図１２９に示すように、光検出装置８００の画素アレイ内の各画素は、ＤＰＤ動作及びＰＤ動作を切り替えて行うことで、イメージング情報及びＴｏＦ情報を切り替えて取得することができるようになっていてもよい。例えば、光検出装置８００は、フレームごとに各画素の動作モードを切り替えることで、イメージング情報及びＴｏＦ情報をそれぞれ取得してもよい。具体的には、光検出装置８００は、ＤＰＤ動作を行うフレームと、ＰＤ動作を行うフレームとを切り替えてセンシングを行うことで、イメージング情報及びＴｏＦ情報をそれぞれ取得してもよい。このとき、光検出装置８００は、全画素一括で動作モードを切り替えてもよく、特定の画素に対して選択的に動作モードを切り替えてもよい。 Alternatively, as shown in FIG. 129, each pixel in the pixel array of the photodetector 800 can be acquired by switching the imaging information and the ToF information by switching between the DPD operation and the PD operation. You may be. For example, the photodetector 800 may acquire imaging information and ToF information by switching the operation mode of each pixel for each frame. Specifically, the photodetector 800 may acquire imaging information and ToF information by switching between a frame that performs a DPD operation and a frame that performs a PD operation for sensing. At this time, the photodetector 800 may switch the operation mode for all pixels at once, or may selectively switch the operation mode for a specific pixel.
　続いて、図１３０を参照して、光検出装置８００においてＤＰＤ動作とＰＤ動作とを切り替える際の具体的な動作の流れについて説明する。図１３０は、本実施形態に係る光検出装置８００のＤＰＤ動作とＰＤ動作とを切り替える際の動作の流れを説明するフローチャート図である。図１３０に示す光検出装置８００では、照度の高低に基づいて、ＤＰＤ動作及びＰＤ動作を切り替えている。 Subsequently, with reference to FIG. 130, a specific operation flow when switching between the DPD operation and the PD operation in the photodetector 800 will be described. FIG. 130 is a flowchart illustrating an operation flow when switching between a DPD operation and a PD operation of the photodetector 800 according to the present embodiment. In the photodetector 800 shown in FIG. 130, the DPD operation and the PD operation are switched based on the high and low illuminance.
　図１３０に示すように、まず、あらかじめＤＰＤ動作及びＰＤ動作の切り替えを行う閾値が設定される（Ｓ１０１）。図１３０に示す動作例では、閾値は、照度に関するパラメータに対して設定される。 As shown in FIG. 130, first, a threshold value for switching between the DPD operation and the PD operation is set in advance (S101). In the operation example shown in FIG. 130, the threshold value is set for a parameter related to illuminance.
　次に、ＤＰＤ動作を行うために、フォトンカウント制御回路がオン状態に制御される（Ｓ１０２）。続いて、光検出装置８００の状態をリセットした（Ｓ１０３）後、光検出装置８００に逆バイアスが印加された後、バイアスが逆バイアスから順バイアスへ反転される（Ｓ１０４）。これにより、光検出装置８００にて光信号が検出される（Ｓ１０５）。 Next, the photon count control circuit is controlled to the ON state in order to perform the DPD operation (S102). Subsequently, after resetting the state of the light detection device 800 (S103), a reverse bias is applied to the light detection device 800, and then the bias is reversed from the reverse bias to the forward bias (S104). As a result, the optical signal is detected by the photodetector 800 (S105).
　さらに、出力パルス数がカウントされ（Ｓ１０６）、カウント値が信号処理回路に出力される（Ｓ１０７）。その後、信号処理回路にて特定の画素のカウント値の平均が算出される（Ｓ１０８）。さらに、算出されたカウント値の平均があらかじめ設定された閾値よりも大きいか否かが判定される（Ｓ１０９）。算出されたカウント値の平均が閾値以下である場合（Ｓ１０９／Ｎｏ）、処理フローはＳ１０２に戻り、光検出装置８００は、引き続き、ＤＰＤ動作を実行する。 Further, the number of output pulses is counted (S106), and the count value is output to the signal processing circuit (S107). After that, the signal processing circuit calculates the average of the count values of the specific pixels (S108). Further, it is determined whether or not the average of the calculated count values is larger than the preset threshold value (S109). When the average of the calculated count values is equal to or less than the threshold value (S109 / No), the processing flow returns to S102, and the photodetector 800 continues to execute the DPD operation.
　一方、算出されたカウント値の平均が閾値より大きい場合（Ｓ１０９／Ｙｅｓ）、処理フローはＳ３０１に移動し、フォトンカウント制御回路がオフ状態に制御される（Ｓ３０１）。さらに、光検出装置８００にてＰＤ動作を行うために、蓄積型フォトダイオード制御回路がオン状態に制御される（Ｓ２０１）。続いて、光検出装置８００の状態をリセットした（Ｓ２０２）後、光検出装置８００に逆バイアスが印加される（Ｓ２０３）。これにより、光検出装置８００にて光電変換された電荷が蓄積する（Ｓ２０４）。その後、蓄積された電荷は、フローティングディフュージョンＦＤに転送され（Ｓ２０５）、光信号が出力される（Ｓ２０６）。 On the other hand, when the average of the calculated count values is larger than the threshold value (S109 / Yes), the processing flow moves to S301 and the photon count control circuit is controlled to the off state (S301). Further, in order to perform the PD operation in the photodetector 800, the storage photodiode control circuit is controlled to be in the ON state (S201). Subsequently, after resetting the state of the photodetector 800 (S202), a reverse bias is applied to the photodetector 800 (S203). As a result, the electric charge converted by photoelectric in the photodetector 800 is accumulated (S204). After that, the accumulated charge is transferred to the floating diffusion FD (S205), and an optical signal is output (S206).
　さらに、出力された光信号の出力電圧が閾値より小さいか否かが判定される（Ｓ２０７）。出力電圧が閾値以上場合（Ｓ２０７／Ｎｏ）、処理フローはＳ２０１に戻り、光検出装置８００は、引き続き、ＰＤ動作を実行する。一方、出力された光信号の出力電圧が閾値より小さい場合（Ｓ２０７／Ｙｅｓ）、処理フローはＳ３０２に移動し、蓄積型フォトダイオード制御回路がオフ状態に制御される（Ｓ３０２）。さらに、光検出装置８００にてＤＰＤ動作を行うために、フォトンカウント制御回路がオン状態に制御される（Ｓ１０２）。 Further, it is determined whether or not the output voltage of the output optical signal is smaller than the threshold value (S207). When the output voltage is equal to or higher than the threshold value (S207 / No), the processing flow returns to S201, and the photodetector 800 continues to execute the PD operation. On the other hand, when the output voltage of the output optical signal is smaller than the threshold value (S207 / Yes), the processing flow moves to S302, and the storage photodiode control circuit is controlled to the off state (S302). Further, in order to perform the DPD operation in the photodetector 800, the photon count control circuit is controlled to the ON state (S102).
　以上の流れの動作例によれば、光検出装置８００は、低照度の場合はＤＰＤ動作によるフォトンカウントを行い、高照度の場合はＰＤ動作によるイメージングを行うことができる。これによれば、光検出装置８００は、低照度ではＤＰＤ動作によるフォトンカウントを行うことでＳ／Ｎを改善し、高照度では蓄積型ＰＤ動作によるイメージングを行うことで消費電力を抑えることができる。 According to the operation example of the above flow, the photodetector 800 can perform photon counting by the DPD operation in the case of low illuminance, and can perform imaging by the PD operation in the case of high illuminance. According to this, the photodetector 800 can improve the S / N by performing photon counting by the DPD operation in low illuminance, and can suppress power consumption by performing imaging by the storage type PD operation in high illuminance. ..
　なお、これらのＤＰＤ動作と蓄積型ＰＤ動作との切り替えの閾値は、例えば、蓄積型ＰＤ動作でＳ／Ｎの顕著な悪化が見られるようになる値に設定されてもよい。例えば、ＤＰＤ動作と蓄積型ＰＤ動作との切り替えの閾値は、１フレームあたりの検出光子数が数百個レベルの値に設定されてもよい。光検出装置８００は、該閾値よりも検出光子数が少なければＰＤＰ動作によるフォトンカウントを行い、検出光子数が多ければ蓄積型ＰＤ動作によるイメージングを行うように制御されてもよい。 The threshold value for switching between the DPD operation and the storage type PD operation may be set to a value at which a remarkable deterioration of S / N is observed in the storage type PD operation, for example. For example, the threshold value for switching between the DPD operation and the storage type PD operation may be set to a value in which the number of detected photons per frame is on the level of several hundreds. The photodetector 800 may be controlled to perform photon counting by the PDP operation if the number of detected photons is smaller than the threshold value, and to perform imaging by the storage type PD operation if the number of detected photons is large.
　（フォトンカウントへの適用例）
　続いて、図１３１～図１３５を参照して、本実施形態に係る光検出装置８００をフォトンカウントに適用する例について説明する。 (Example of application to photon count)
Subsequently, an example of applying the photodetector 800 according to the present embodiment to the photon count will be described with reference to FIGS. 131 to 135.
　まず、図１３１及び図１３２を参照して、ＤＰＤによるフォトンカウント動作の概要について説明する。図１３１は、ＤＰＤによるフォトンカウント動作の概要を示すブロック図である。図１３２は、ＤＰＤに入射した光子と、検出される信号との対応関係を示すグラフ図である。 First, the outline of the photon counting operation by DPD will be described with reference to FIGS. 131 and 132. FIG. 131 is a block diagram showing an outline of the photon counting operation by DPD. FIG. 132 is a graph showing the correspondence between the photon incident on the DPD and the detected signal.
　図１３１及び図１３２に示すように、ＤＰＤによるフォトンカウント動作では、まず、照明光を対象物にて反射した光を光受信機で受信する。受信された光は、ＤＰＤなどの光受信機で電気信号に変換されることで、受信光パルスとなる。そこで、カウンター回路は、受信光パルスをカウントすることで、受信光パルスの数に応じたカウンター信号を生成することができる。カウンター信号は、光子数に対応する強度を有する情報である。その後、画像処理回路は、生成されたカウンター信号を信号処理することで画像情報を取得することができる。 As shown in FIGS. 131 and 132, in the photon counting operation by DPD, first, the light reflected by the object is received by the optical receiver. The received light is converted into an electric signal by an optical receiver such as a DPD to become a received light pulse. Therefore, the counter circuit can generate a counter signal according to the number of received light pulses by counting the received light pulses. The counter signal is information having an intensity corresponding to the number of photons. After that, the image processing circuit can acquire image information by signal processing the generated counter signal.
　また、図１３３～図１３４Ｃを参照して、本実施形態に係る光検出装置８００を１光子入射が検出可能なＤＰＤとして構成した場合のフォトンカウント動作の一例について説明する。 Further, with reference to FIGS. 133 to 134C, an example of a photon counting operation when the photodetector 800 according to the present embodiment is configured as a DPD capable of detecting one photon incident will be described.
　図１３３は、本実施形態に係る光検出装置８００のフォトンカウント動作の一例を示すタイミングチャート図である。図１３４Ａは、図１３３の（１）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１３４Ｂは、図１３３の（２）のタイミングにおける光検出装置８００の状態を説明する縦断面図であり、図１３４Ｃは、図１３３の（３）のタイミングにおける光検出装置８００の状態を説明する縦断面図である。 FIG. 133 is a timing chart showing an example of the photon counting operation of the photodetector 800 according to the present embodiment. FIG. 134A is a vertical cross-sectional view illustrating the state of the photodetector 800 at the timing of FIG. 133 (1), and FIG. 134B describes the state of the photodetector 800 at the timing of FIG. 133 (2). It is a vertical cross-sectional view, and FIG. 134C is a vertical cross-sectional view illustrating a state of the photodetector 800 at the timing of FIG. 133 (3).
　図１３３及び図１３４Ａに示すように、まず、図１３３の（１）のタイミングで、スイッチトランジスタＳＷのゲートに印加される電圧ＶＳＷに正電圧を印加することで、スイッチトランジスタＳＷをオン状態とする。続いて、第２電極８２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。このとき、第１電極８１１に印加される電圧Ｖｃは、０Ｖであるため、光検出装置８００の第１領域８１０及び第２領域８２０の間には、逆バイアスが印加されることになる。なお、制御ゲートＣＧに印加される電圧Ｖｃｏｎは、負電圧（例えば、－１Ｖ）に設定する。 As shown in FIGS. 133 and 134A, first, at the timing of (1) in FIG. 133, a positive voltage is applied to the voltage V SW applied to the gate of the switch transistor SW to turn on the switch transistor SW. To do. Subsequently, the voltage Va applied to the second electrode 821 is set to a negative voltage (for example, -1V). At this time, since the voltage Vc applied to the first electrode 811 is 0 V, a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800. The voltage V con applied to the control gate CG is set to a negative voltage (for example, -1V).
　ここで、図１３３及び図１３４Ｂに示すように、図１３３の（２）のタイミングで、第２電極８２１に印加される電圧Ｖａを正電圧（例えば、＋１Ｖ）とすることで、光検出装置８００の第１領域８１０及び第２領域８２０の間に順バイアスを印加する。また、制御ゲートＣＧに印加される電圧Ｖｃｏｎを正電圧（例えば、＋１Ｖ）に設定する。 Here, as shown in FIGS. 133 and 134B, the photodetector 800 is set to a positive voltage (for example, + 1V) by setting the voltage Va applied to the second electrode 821 at the timing of (2) in FIG. 133. A forward bias is applied between the first region 810 and the second region 820. Further, the voltage V con applied to the control gate CG is set to a positive voltage (for example, + 1V).
　このとき、光検出装置８００に光子が入射した場合、第３領域８３０での光電変換によって第２電極８２１に電流パルスが出力されるため、出力された電流パルスを波形検出器で検出することで、入射した光子をカウンターにて計測することができる。したがって、光検出装置８００は、ＤＰＤによるフォトンカウント動作にて１光子入射を検出することができる。 At this time, when a photon is incident on the photodetector 800, a current pulse is output to the second electrode 821 by photoelectric conversion in the third region 830. Therefore, the output current pulse can be detected by the waveform detector. , The incident photon can be measured with a counter. Therefore, the photodetector 800 can detect one photon incident by the photon counting operation by DPD.
　さらに、図１３３及び図１３４Ｃに示すように、図１３３の（３）のタイミングで第２電極８２１に印加される電圧Ｖａを負電圧（例えば、－１Ｖ）とする。これにより、光検出装置８００の第１領域８１０及び第２領域８２０の間には逆バイアスが印加されるため、光検出装置８００の状態がリセットされる。なお、制御ゲートＣＧに印加される電圧Ｖｃｏｎも同様に負電圧（例えば、－１Ｖ）に設定してもよい。 Further, as shown in FIGS. 133 and 134C, the voltage Va applied to the second electrode 821 at the timing of (3) in FIG. 133 is set to a negative voltage (for example, -1V). As a result, a reverse bias is applied between the first region 810 and the second region 820 of the photodetector 800, so that the state of the photodetector 800 is reset. The voltage V con applied to the control gate CG may also be set to a negative voltage (for example, -1V).
　以上の動作を（１）から（３）までの時間をカウント周期として繰り返すことで、光検出装置８００は、ＤＰＤによるフォトンカウント動作を行うことができる。 By repeating the above operation with the time from (1) to (3) as the counting cycle, the photodetector 800 can perform the photon counting operation by DPD.
　（フォトンカウント動作を実行する画素アレイの回路構造）
　さらに、図１３５を参照して、本実施形態に係る光検出装置８００において、フォトンカウント動作を実行する画素アレイの回路構成の一例について説明する。図１３５は、フォトンカウント動作を実行する画素アレイに本実施形態に係る光検出装置８００を適用した場合の機能構成を示すブロック図である。 (Circuit structure of pixel array that executes photon counting operation)
Further, with reference to FIG. 135, an example of a circuit configuration of a pixel array that executes a photon counting operation in the photodetector 800 according to the present embodiment will be described. FIG. 135 is a block diagram showing a functional configuration when the photodetector 800 according to the present embodiment is applied to the pixel array that executes the photon counting operation.
　図１３５に示すように、各画素の光電変換部ＤＰＤ／ＰＤには、ＤＰＤ制御回路８０１、ＤＰＤ信号検出回路８０３、ＰＤ制御回路８０２、ＰＤ信号検出回路８０４、及びカウンター回路８０５が接続される。 As shown in FIG. 135, a DPD control circuit 801 and a DPD signal detection circuit 803, a PD control circuit 802, a PD signal detection circuit 804, and a counter circuit 805 are connected to the photoelectric conversion unit DPD / PD of each pixel.
　各画素のＤＰＤ制御回路８０１、ＤＰＤ信号検出回路８０３、及びカウンター回路８０５は、ＤＰＤ水平制御部８２１０、ＤＰＤ信号処理部８２２０、及び垂直制御部８３００と接続される。また、各画素のＰＤ制御回路８０２及びＰＤ信号検出回路８０４は、ＰＤ水平制御部８１１０、ＰＤ信号処理部８１２０、及び垂直制御部８３００と接続される。また、各画素は、光電変換部ＤＰＤ／ＰＤのＤＰＤ動作又はＰＤ動作の切り替えを行うＤＰＤ／ＰＤ切替制御部８４００と接続される。 The DPD control circuit 801 and the DPD signal detection circuit 803 and the counter circuit 805 of each pixel are connected to the DPD horizontal control unit 8210, the DPD signal processing unit 8220, and the vertical control unit 8300. Further, the PD control circuit 802 and the PD signal detection circuit 804 of each pixel are connected to the PD horizontal control unit 8110, the PD signal processing unit 8120, and the vertical control unit 8300. Further, each pixel is connected to the DPD / PD switching control unit 8400 that switches the DPD operation or the PD operation of the photoelectric conversion unit DPD / PD.
　ＤＰＤ／ＰＤ切替制御部８４００は、ＤＰＤ水平制御部８２１０、ＰＤ水平制御部８１１０、及び各画素と接続される。ＤＰＤ／ＰＤ切替制御部８４００は、ＤＰＤ／ＰＤ切替信号を出力することで、各画素のＤＰＤ／ＰＤ動作を切り替える。 The DPD / PD switching control unit 8400 is connected to the DPD horizontal control unit 8210, the PD horizontal control unit 8110, and each pixel. The DPD / PD switching control unit 8400 switches the DPD / PD operation of each pixel by outputting the DPD / PD switching signal.
　なお、ＤＰＤ／ＰＤ動作の切り替えは、用途に応じて、全画素一括で行われてもよく、画素アレイの所定の画素ごとに行われてもよい。また、ＤＰＤ／ＰＤ動作の切り替えは、時間を区切って行われてもよく、フレームごとに行われてもよい。 Note that the DPD / PD operation switching may be performed for all pixels at once or for each predetermined pixel of the pixel array, depending on the application. Further, the switching of the DPD / PD operation may be performed by dividing the time, or may be performed for each frame.
　垂直制御部８３００は、ＤＰＤ水平制御部８２１０及びＰＤ水平制御部８１１０に接続され、光電変換部ＤＰＤ／ＰＤにてＤＰＤ動作及びＰＤ動作が行われた際に、ＤＰＤ水平制御部８２１０及びＰＤ水平制御部８１１０に行ごとに読み出し信号を出力する。 The vertical control unit 8300 is connected to the DPD horizontal control unit 8210 and the PD horizontal control unit 8110, and when the DPD operation and the PD operation are performed by the photoelectric conversion unit DPD / PD, the DPD horizontal control unit 8210 and the PD horizontal control unit 8300 are controlled. A read signal is output to unit 8110 line by line.
　ＤＰＤ水平制御部８２１０は、行ごとの読み出し信号が入力された場合、列ごとに各画素のＤＰＤ信号を読み出し、読み出したＤＰＤ信号をＤＰＤ信号処理部８２２０に出力する。 When the read signal for each row is input, the DPD horizontal control unit 8210 reads the DPD signal of each pixel for each column and outputs the read DPD signal to the DPD signal processing unit 8220.
　ＤＰＤ信号処理部８２２０は、入力されたＤＰＤ信号を信号処理した後、信号処理されたＤＰＤ信号をフォトンカウントデータとして出力する。 The DPD signal processing unit 8220 processes the input DPD signal and then outputs the signal-processed DPD signal as photon count data.
　ＰＤ水平制御部８１１０は、行ごとの読み出し信号が入力された場合、列ごとに各画素のＰＤ信号を読み出し、読み出したＰＤ信号をＰＤ信号処理部８１２０に出力する。 When the read signal for each row is input, the PD horizontal control unit 8110 reads the PD signal of each pixel for each column and outputs the read PD signal to the PD signal processing unit 8120.
　ＰＤ信号処理部８１２０は、入力されたＰＤ信号を信号処理した後、信号処理されたＰＤ信号を画像データとして出力する。 The PD signal processing unit 8120 processes the input PD signal and then outputs the processed PD signal as image data.
　以上にて説明したように、本実施形態に係る光検出装置８００は、ＰＤ動作を用いたイメージセンサ、及びＤＰＤ動作を用いたＴｏＦセンサとしてだけではく、ＤＰＤ動作を用いたフォトンカウンタとしても用いることが可能である。 As described above, the photodetector 800 according to the present embodiment is used not only as an image sensor using PD operation and a ToF sensor using DPD operation, but also as a photon counter using DPD operation. It is possible.
　＜７．第７の実施形態＞
　（基本構造）
　続いて、図１３６～図１４０を参照して、本開示の第７の実施形態に係る光検出装置の基本構造について説明する。図１３６は、本実施形態に係る光検出装置９００の構造を示す縦断面図である。図１３７は、光検出装置９００から出力される電流の時間応答のばらつきを説明するグラフ図であり、図１３８は、図１３７に示す時間応答のばらつきに対する線形性のずれを示すグラフ図である。図１３９は、本実施形態に係る光検出装置９００の画素アレイ構成を示す平面図である。図１４０は、図１３９に示す画素アレイにおける通常画素ＮＰの出力と、参照画素ＯＢＰの出力との関係を示すグラフ図である。 <7. Seventh Embodiment>
(Basic structure)
Subsequently, with reference to FIGS. 136 to 140, the basic structure of the photodetector according to the seventh embodiment of the present disclosure will be described. FIG. 136 is a vertical cross-sectional view showing the structure of the photodetector 900 according to the present embodiment. FIG. 137 is a graph diagram for explaining the variation in the time response of the current output from the photodetector 900, and FIG. 138 is a graph diagram showing the deviation in linearity with respect to the variation in the time response shown in FIG. 137. FIG. 139 is a plan view showing a pixel array configuration of the photodetector 900 according to the present embodiment. FIG. 140 is a graph showing the relationship between the output of the normal pixel NP and the output of the reference pixel OBP in the pixel array shown in FIG. 139.
　図１３６に示すように、光検出装置９００は、例えば、第１領域９１０と、第２領域９２０と、第３領域９３０と、制御ゲート９６３と、ゲート絶縁膜９６４とを備える。 As shown in FIG. 136, the photodetector 900 includes, for example, a first region 910, a second region 920, a third region 930, a control gate 963, and a gate insulating film 964.
　第１領域９１０は、シリコン（Ｓｉ）などの半導体基板の第１面側に設けられた第１導電型の領域（例えば、Ｎ＋層）である。第２領域９２０は、シリコン（Ｓｉ）などの半導体基板の第１面と反対側の第２面側に設けられた第２導電型の領域（例えば、Ｐ＋層）である。第３領域９３０は、シリコン（Ｓｉ）などの半導体基板の第１領域９１０と第２領域９２０との間に設けられた第３導電型の領域（例えば、ｉ層）である。 The first region 910 is a first conductive type region (for example, N + layer) provided on the first surface side of a semiconductor substrate such as silicon (Si). The second region 920 is a second conductive type region (for example, P + layer) provided on the second surface side opposite to the first surface of the semiconductor substrate such as silicon (Si). The third region 930 is a third conductive type region (for example, layer i) provided between the first region 910 and the second region 920 of a semiconductor substrate such as silicon (Si).
　第１領域９１０は、例えば、半導体基板の第１面の上に設けられた第１電極（図示せず）と電気的に接続される。第１電極は、例えば、カソード電極として機能する。また、第２領域９２０は、半導体基板の第２面の上に設けられた第２電極（図示せず）と電気的に接続される。第２電極は、例えば、アノード電極として機能する。 The first region 910 is electrically connected to, for example, a first electrode (not shown) provided on the first surface of the semiconductor substrate. The first electrode functions as, for example, a cathode electrode. Further, the second region 920 is electrically connected to a second electrode (not shown) provided on the second surface of the semiconductor substrate. The second electrode functions as, for example, an anode electrode.
　制御ゲート９６３は、半導体基板の第２面の上にゲート絶縁膜９６４を介して設けられるゲート電極である。制御ゲート９６３は、電圧印加によって、第３領域９３０におけるポテンシャル障壁を制御することができる。 The control gate 963 is a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film 964. The control gate 963 can control the potential barrier in the third region 930 by applying a voltage.
　光検出装置９００では、入射する光量の大きさを、逆バイアスから順バイアスにバイアスの極性が反転された際の順電流の立ち上がり時間の遅延の大きさとして出力する。ただし、光検出装置９００が複数の画素を配列した画素アレイとして構成される場合、画素アレイ内の局所的な温度変化、又は各画素のプロファイルのずれによって、各画素にて入射光量と、順電流の遅延特性との関係性にばらつきが生じることがあり得る。 The photodetector 900 outputs the magnitude of the incident light amount as the magnitude of the delay in the rise time of the forward current when the polarity of the bias is reversed from the reverse bias to the forward bias. However, when the photodetector 900 is configured as a pixel array in which a plurality of pixels are arranged, the amount of incident light and the forward current in each pixel are caused by a local temperature change in the pixel array or a deviation in the profile of each pixel. There may be variations in the relationship with the delay characteristics of.
　具体的には、図１３７に示すように、逆バイアスから順バイアスにバイアスの極性を反転させた後の順電流の立ち上がり時刻が画素アレイの画素ごとにばらつくことがあり得る。このような場合、図１３８に示すように、画素によっては、入射光量と、順電流の立ち上がりの遅延時間との間の線形性にずれが生じることがあり得る。また、画素ごとに、入射光量と、順電流の立ち上がりの遅延時間との関係性に異なるオフセットが生じることがあり得る。 Specifically, as shown in FIG. 137, the rising time of the forward current after reversing the polarity of the bias from the reverse bias to the forward bias may vary from pixel to pixel in the pixel array. In such a case, as shown in FIG. 138, depending on the pixel, there may be a deviation in the linearity between the amount of incident light and the delay time for the rise of the forward current. Further, for each pixel, a different offset may occur in the relationship between the amount of incident light and the delay time for the rise of the forward current.
　本実施形態に係る光検出装置９００では、図１３９に示すように、画素アレイ内に、通常画素ＮＰに隣接して参照画素ＯＢＰが設けられる。通常画素ＮＰは、入射光を光電変換し、入射光に応じた出力を発する画素である。参照画素ＯＢＰは、入射光の入射面に入射光を遮る遮光部が設けられ、入射光に依らない出力を発する画素である。参照画素ＯＢＰは、オプティカルブラック（Ｏｐｔｉｃａｌ　Ｂｌａｃｋ）画素とも称される。 In the photodetector 900 according to the present embodiment, as shown in FIG. 139, a reference pixel OBP is provided in the pixel array adjacent to the normal pixel NP. A normal pixel NP is a pixel that photoelectrically converts incident light and emits an output according to the incident light. The reference pixel OBP is a pixel that is provided with a light-shielding portion that blocks the incident light on the incident surface of the incident light and emits an output that does not depend on the incident light. The reference pixel OBP is also referred to as an optical black pixel.
　光検出装置９００は、図１４０に示すように、参照画素ＯＢＰにおける順電流の立ち上がり時刻を基準として、通常画素ＮＰにおける順電流の立ち上がり時刻の遅延を算出することで、入射光量に応じた順電流の立ち上がり時刻の遅延をより高い精度で検出することができる。さらに、本実施形態に係る光検出装置９００では、通常画素ＮＰに隣接して参照画素ＯＢＰが設けられるため、画素アレイ内の局所的な温度変化、又は各画素のプロファイルのずれ等によるばらつきの影響をより抑制することができる。例えば、参照画素ＯＢＰは、図１３９に示すように、行列状に配列された通常画素ＮＰの外縁に沿って設けられてもよい。 As shown in FIG. 140, the photodetector 900 calculates the delay of the rising time of the forward current in the normal pixel NP with reference to the rising time of the forward current in the reference pixel OBP, so that the forward current corresponds to the amount of incident light. It is possible to detect the delay of the rising time of the above with higher accuracy. Further, in the photodetector 900 according to the present embodiment, since the reference pixel OBP is provided adjacent to the normal pixel NP, the influence of variation due to local temperature change in the pixel array, deviation of the profile of each pixel, or the like. Can be further suppressed. For example, the reference pixel OBP may be provided along the outer edge of the normal pixels NP arranged in a matrix as shown in FIG. 139.
　したがって、本実施形態に係る光検出装置９００によれば、複数の画素を配列した画素アレイにおける各画素の出力のばらつきを抑制することができるため、入射光の光量をより高い精度で検出することができる。 Therefore, according to the photodetector 900 according to the present embodiment, it is possible to suppress variations in the output of each pixel in a pixel array in which a plurality of pixels are arranged, so that the amount of incident light can be detected with higher accuracy. Can be done.
　（バリエーション）
　続いて、図１４１～図１４９を参照して、本実施形態に係る光検出装置９００の構造のバリエーションについて説明する。 (variation)
Subsequently, with reference to FIGS. 141 to 149, variations in the structure of the photodetector 900 according to the present embodiment will be described.
　（第１のバリエーション）
　図１４１は、通常画素ＮＰと、参照画素ＯＢＰとの平面配置の第１のバリエーションを説明する模式的な平面図である。図１４２は、図１４１のＡ－ＡＡ切断面における断面構成を示す縦断面図である。 (First variation)
FIG. 141 is a schematic plan view illustrating a first variation of the plane arrangement of the normal pixel NP and the reference pixel OBP. FIG. 142 is a vertical cross-sectional view showing a cross-sectional structure of the AA cut surface of FIG. 141.
　図１４１に示すように、画素アレイ内において、通常画素ＮＰと、参照画素ＯＢＰとは、市松格子状（チェッカーフラッグ柄状）に配列されてもよい。具体的には、通常画素ＮＰ及び参照画素ＯＢＰは、行列配列の行方向及び列方向のそれぞれにて交互に配置されてもよい。 As shown in FIG. 141, the normal pixel NP and the reference pixel OBP may be arranged in a checkered grid pattern (checkered flag pattern pattern) in the pixel array. Specifically, the normal pixel NP and the reference pixel OBP may be arranged alternately in the row direction and the column direction of the matrix array.
　このような場合、図１４２に示すように、互いに隣接する通常画素ＮＰ及び参照画素ＯＢＰは、絶縁体を含む画素分離層９５０にて互いに電気的に分離されており、それぞれ第１領域９１０、第２領域９２０、及び第３領域９３０を同様に備える。ただし、参照画素ＯＢＰには、例えば、第１領域９１０の入射面側に金属等を含む遮光部ＢＭが設けられる。これにより、第３領域９３０への光の入射が遮られるため、参照画素ＯＢＰは、入射光に依らない出力を発することができる。 In such a case, as shown in FIG. 142, the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are separated from each other, respectively. The two regions 920 and the third region 930 are similarly provided. However, the reference pixel OBP is provided with, for example, a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910. As a result, the incident light on the third region 930 is blocked, so that the reference pixel OBP can emit an output that does not depend on the incident light.
　通常画素ＮＰ及び参照画素ＯＢＰからの出力は、出力回路Ｏｕｔに入力される。出力回路Ｏｕｔは、隣接する参照画素ＯＢＰにおける順電流の立ち上がり時刻を基準とすることで、通常画素ＮＰにおける順電流の立ち上がり時刻の遅延をより高い精度で検出することができる。 The output from the normal pixel NP and the reference pixel OBP is input to the output circuit Out. The output circuit Out can detect the delay of the rising time of the forward current in the normal pixel NP with higher accuracy by using the rising time of the forward current in the adjacent reference pixel OBP as a reference.
　第１のバリエーションによれば、画素アレイ内において、通常画素ＮＰと、参照画素ＯＢＰとが交互に配置されるため、画素アレイ内の面内方向のばらつきによる影響をさらに抑制することができる。 According to the first variation, since the normal pixel NP and the reference pixel OBP are alternately arranged in the pixel array, the influence of the variation in the in-plane direction in the pixel array can be further suppressed.
　（第２のバリエーション）
　図１４３は、通常画素ＮＰと、参照画素ＯＢＰとの平面配置の第２のバリエーションを説明する模式的な平面図である。図１４４は、図１４３のＢ－ＢＢ切断面における断面構成を示す縦断面図である。 (Second variation)
FIG. 143 is a schematic plan view illustrating a second variation of the plane arrangement of the normal pixel NP and the reference pixel OBP. FIG. 144 is a vertical cross-sectional view showing a cross-sectional structure of the B-BB cut surface of FIG. 143.
　図１４３に示すように、画素アレイ内において、通常画素ＮＰと、参照画素ＯＢＰとは、異なる平面面積で設けられてもよい。具体的には、参照画素ＯＢＰは、通常画素ＮＰよりも小さい平面面積で設けられてもよい。 As shown in FIG. 143, the normal pixel NP and the reference pixel OBP may be provided in different plane areas in the pixel array. Specifically, the reference pixel OBP may be provided with a plane area smaller than that of the normal pixel NP.
　例えば、通常画素ＮＰ及び参照画素ＯＢＰは、行列配列の第１方向（図１４３では列方向）に連続して配列され、行列配列の第１方向と直交する第２方向（図１４３では行方向）に交互に配列されてもよい。このとき、参照画素ＯＢＰは、第２方向（図１４３では行方向）にて通常画素ＮＰよりも小さい幅で設けられることで、通常画素ＮＰよりも小さい平面面積で設けられてもよい。 For example, the normal pixel NP and the reference pixel OBP are continuously arranged in the first direction of the matrix array (column direction in FIG. 143), and are arranged in the second direction orthogonal to the first direction of the matrix array (row direction in FIG. 143). May be alternately arranged in. At this time, the reference pixel OBP may be provided in a plane area smaller than that of the normal pixel NP by being provided with a width smaller than that of the normal pixel NP in the second direction (row direction in FIG. 143).
　このような場合、図１４４に示すように、互いに隣接する通常画素ＮＰ及び参照画素ＯＢＰは、絶縁体を含む画素分離層９５０にて互いに電気的に分離されており、それぞれ第１領域９１０、第２領域９２０（第２領域９２０Ｎ、９２０Ｂ）、及び第３領域９３０を備える。また、参照画素ＯＢＰは、第１領域９１０の入射面側に金属等を含む遮光部ＢＭをさらに備える。 In such a case, as shown in FIG. 144, the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are separated from each other, respectively. It includes two regions 920 (second regions 920N, 920B) and a third region 930. Further, the reference pixel OBP further includes a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910.
　ここで、通常画素ＮＰの第２領域９２０Ｎと、参照画素ＯＢＰの第２領域９２０Ｂとは、同じ大きさとなるように設けられる。出力回路Ｏｕｔへの出力を取り出す第２領域９２０Ｎ、９２０Ｂの大きさは、順電流の立ち上がり時刻を決定する主要因となる。そのため、通常画素ＮＰ及び参照画素ＯＢＰは、第２領域９２０Ｎ、９２０Ｂの大きさを同じとすることで、順電流の立ち上がり時刻の基準を揃えることができる。これによれば、出力回路Ｏｕｔは、参照画素ＯＢＰでの順電流の立ち上がり時刻を基準として、通常画素ＮＰでの順電流の立ち上がり時刻の遅延を検出することができる。 Here, the second region 920N of the normal pixel NP and the second region 920B of the reference pixel OBP are provided so as to have the same size. The size of the second regions 920N and 920B from which the output to the output circuit Out is taken out is a main factor for determining the rise time of the forward current. Therefore, the normal pixel NP and the reference pixel OBP have the same size of the second regions 920N and 920B, so that the reference of the rising time of the forward current can be aligned. According to this, the output circuit Out can detect the delay of the rising time of the forward current in the normal pixel NP with reference to the rising time of the forward current in the reference pixel OBP.
　第２のバリエーションによれば、画素アレイ内において、遮光部ＢＭを備える参照画素ＯＢＰの平面面積を通常画素ＮＰの平面面積よりも小さくすることで、画素アレイ内の開口率を向上させることができる。 According to the second variation, the aperture ratio in the pixel array can be improved by making the plane area of the reference pixel OBP including the light-shielding portion BM smaller than the plane area of the normal pixel NP in the pixel array. ..
　（第３のバリエーション）
　図１４５は、通常画素ＮＰと、参照画素ＯＢＰとの平面配置の第３のバリエーションを説明する模式的な平面図である。図１４６は、図１４５のＣ－ＣＣ切断面における断面構成を示す縦断面図である。 (Third variation)
FIG. 145 is a schematic plan view illustrating a third variation of the plane arrangement of the normal pixel NP and the reference pixel OBP. FIG. 146 is a vertical cross-sectional view showing a cross-sectional structure of the C-CC cut surface of FIG. 145.
　図１４５に示すように、画素アレイ内において、参照画素ＯＢＰは、複数の通常画素ＮＰごとに設けられてもよい。例えば、参照画素ＯＢＰは、３つの通常画素ＮＰに対して１つの割合で周期的に設けられてもよい。 As shown in FIG. 145, the reference pixel OBP may be provided for each of a plurality of normal pixel NPs in the pixel array. For example, the reference pixel OBP may be periodically provided at a ratio of 1 to 3 normal pixels NP.
　このような場合、図１４６に示すように、互いに隣接する通常画素ＮＰ及び参照画素ＯＢＰは、絶縁体を含む画素分離層９５０にて互いに電気的に分離されており、それぞれ第１領域９１０、第２領域９２０、及び第３領域９３０を備える。また、参照画素ＯＢＰは、例えば、第１領域９１０の入射面側に金属等を含む遮光部ＢＭをさらに備える。これにより、第３領域９３０への光の入射が遮られるため、参照画素ＯＢＰは、入射光に依らない出力を発することができる。 In such a case, as shown in FIG. 146, the normal pixel NP and the reference pixel OBP adjacent to each other are electrically separated from each other by the pixel separation layer 950 including the insulator, and the first region 910 and the reference pixel OBP are respectively separated. It includes two regions 920 and a third region 930. Further, the reference pixel OBP further includes, for example, a light-shielding portion BM containing a metal or the like on the incident surface side of the first region 910. As a result, the incident light on the third region 930 is blocked, so that the reference pixel OBP can emit an output that does not depend on the incident light.
　第３のバリエーションによれば、画素アレイ内において、遮光部ＢＭを備える参照画素ＯＢＰの通常画素ＮＰに対する割合を少なくすることができるため、画素アレイ内の開口率を向上させることができる。このような場合でも、光検出装置９００は、画素アレイ内の面内方向のばらつきによる影響を十分に抑制することができる。 According to the third variation, the ratio of the reference pixel OBP provided with the light-shielding portion BM to the normal pixel NP can be reduced in the pixel array, so that the aperture ratio in the pixel array can be improved. Even in such a case, the photodetector 900 can sufficiently suppress the influence of the variation in the in-plane direction in the pixel array.
　（第４のバリエーション）
　図１４７は、通常画素ＮＰと、参照画素ＯＢＰとの平面配置の第４のバリエーションを説明する模式的な平面図である。 (Fourth variation)
FIG. 147 is a schematic plan view illustrating a fourth variation of the plane arrangement of the normal pixel NP and the reference pixel OBP.
　図１４７に示すように、通常画素ＮＰが行列状に配列された画素アレイ内において、参照画素ＯＢＰは、周期的に設けられてもよい。例えば、参照画素ＯＢＰは、８行×８列の画素群に１つの割合で周期的に設けられてもよい。 As shown in FIG. 147, the reference pixel OBP may be periodically provided in the pixel array in which the normal pixel NPs are arranged in a matrix. For example, the reference pixel OBP may be periodically provided at a ratio of 1 in a pixel group of 8 rows × 8 columns.
　このような場合、通常画素ＮＰに対する参照画素ＯＢＰの割合が少なくなるため、光検出装置９００は、動作時に、それぞれの参照画素ＯＢＰからの順電流の立ち上がり時間をモニタリングすることが望ましい。光検出装置９００は、モニタリング結果に基づいて、例えば、参照画素ＯＢＰからの出力の補正又は校正を行ったり、所定の基準に基づいてアラートを挙げたりしてもよい。 In such a case, since the ratio of the reference pixel OBP to the normal pixel NP is small, it is desirable that the photodetector 900 monitors the rising time of the forward current from each reference pixel OBP during operation. The photodetector 900 may, for example, correct or calibrate the output from the reference pixel OBP based on the monitoring results, or raise an alert based on a predetermined criterion.
　第４のバリエーションによれば、画素アレイ内において、遮光部ＢＭを備える参照画素ＯＢＰの通常画素ＮＰに対する割合を少なくすることができるため、画素アレイ内の開口率を向上させることができる。このような場合でも、光検出装置９００は、画素アレイ内の面内方向のばらつきによる影響を十分に抑制することができる。 According to the fourth variation, the ratio of the reference pixel OBP provided with the light-shielding portion BM to the normal pixel NP can be reduced in the pixel array, so that the aperture ratio in the pixel array can be improved. Even in such a case, the photodetector 900 can sufficiently suppress the influence of the variation in the in-plane direction in the pixel array.
　（第５のバリエーション）
　図１４８は、通常画素ＮＰと、参照画素ＯＢＰとの断面構成の第５のバリエーションを示す縦断面図である。図１４９は、参照画素ＯＢＰの開口面積と、順電流の立ち上がりの遅延時間との対応関係を示すグラフ図である。 (Fifth variation)
FIG. 148 is a vertical cross-sectional view showing a fifth variation of the cross-sectional configuration of the normal pixel NP and the reference pixel OBP. FIG. 149 is a graph showing the correspondence between the opening area of the reference pixel OBP and the delay time for the rise of the forward current.
　図１４８に示すように、画素アレイ内に設けられた参照画素ＯＢＰの各々は、光の入射面に設けられた遮光部ＢＭの面積が互いに異なるように設けられてもよい。例えば、複数の参照画素ＯＢＰ１、ＯＢＰ２、ＯＢＰ３、ＯＢＰ４、ＯＢＰ５、ＯＢＰ６では、遮光部ＢＭ１、ＢＭ２、ＢＭ３、ＢＭ４、ＢＭ５、ＢＭ６の面積はこの順に小さくなるように設けられてもよい。 As shown in FIG. 148, each of the reference pixels OBP provided in the pixel array may be provided so that the areas of the light-shielding portions BM provided on the incident surface of the light are different from each other. For example, in the plurality of reference pixels OBP1, OBP2, OBP3, OBP4, OBP5, and OBP6, the areas of the light-shielding portions BM1, BM2, BM3, BM4, BM5, and BM6 may be provided so as to be smaller in this order.
　このような場合、図１４９に示すように、光検出装置９００は、遮光部ＢＭによる開口面積の変化と、順電流の立ち上がりの遅延時間との対応関係を示す検量線を作成することができる。したがって、光検出装置９００は、入射光の光量ごとに該検量線を作成することで、１光子が入射した場合の順電流の立ち上がりの遅延時間、又は測定のダイナミックレンズ等を簡易的に確認することが可能である。 In such a case, as shown in FIG. 149, the photodetector 900 can create a calibration curve showing the correspondence between the change in the opening area due to the light-shielding portion BM and the delay time for the rise of the forward current. Therefore, the photodetector 900 simply creates the calibration curve for each amount of incident light to easily confirm the delay time of the rise of the forward current when one photon is incident, the dynamic lens for measurement, or the like. It is possible.
　（画素アレイの回路構造）
　さらに、図１５０～図１５３を参照して、本実施形態に係る光検出装置９００を複数の画素が行列状に配列された画素アレイとして構成した場合の第１～第４の回路構成について説明する。 (Pixel array circuit structure)
Further, with reference to FIGS. 150 to 153, the first to fourth circuit configurations when the photodetector 900 according to the present embodiment is configured as a pixel array in which a plurality of pixels are arranged in a matrix will be described. ..
　（第１の回路構成）
　図１５０は、本実施形態に係る光検出装置９００を画素アレイとした場合の第１の回路構成を示すブロック図である。 (First circuit configuration)
FIG. 150 is a block diagram showing a first circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
　図１５０に示すように、通常画素ＮＰ及び参照画素ＯＢＰは、光電変換部ＤＰＤ／ＰＤと、駆動回路９０１と、波形検出部９０２と、カウンター９０３とを備える。光電変換部ＤＰＤ／ＰＤから出力された電荷又は電流は、波形検出部９０２にて検出された後、カウンター９０３に計測される。また、駆動回路９０１は、波形検出部９０２にて検出された電荷又は電流に基づいて、光電変換部ＤＰＤ／ＰＤの駆動を制御する。 As shown in FIG. 150, the normal pixel NP and the reference pixel OBP include a photoelectric conversion unit DPD / PD, a drive circuit 901, a waveform detection unit 902, and a counter 903. The electric charge or current output from the photoelectric conversion unit DPD / PD is detected by the waveform detection unit 902 and then measured by the counter 903. Further, the drive circuit 901 controls the drive of the photoelectric conversion unit DPD / PD based on the electric charge or the current detected by the waveform detection unit 902.
　通常画素ＮＰ及び参照画素ＯＢＰは、垂直制御部９３００及び水平制御部９０１０の制御によってそれぞれ出力が読み出される。読み出された出力は、信号処理部９０２０にて信号処理された後、画像出力として出力される。第１の回路構成に示すように、参照画素ＯＢＰは、通常画素ＮＰの外縁部に配置されてもよい。 The outputs of the normal pixel NP and the reference pixel OBP are read out under the control of the vertical control unit 9300 and the horizontal control unit 9010, respectively. The read output is signal-processed by the signal processing unit 9020 and then output as an image output. As shown in the first circuit configuration, the reference pixel OBP may be arranged at the outer edge portion of the normal pixel NP.
　（第２の回路構成）
　図１５１は、本実施形態に係る光検出装置９００を画素アレイとした場合の第２の回路構成を示すブロック図である。 (Second circuit configuration)
FIG. 151 is a block diagram showing a second circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
　図１５１に示すように、通常画素ＮＰ及び参照画素ＯＢＰは、光電変換部ＤＰＤ／ＰＤと、駆動回路９０１と、波形検出部９０２と、カウンター９０３とを備える。光電変換部ＤＰＤ／ＰＤから出力された電荷又は電流は、波形検出部９０２にて検出された後、カウンター９０３に計測される。また、駆動回路９０１は、波形検出部９０２にて検出された電荷又は電流に基づいて、光電変換部ＤＰＤ／ＰＤの駆動を制御する。 As shown in FIG. 151, the normal pixel NP and the reference pixel OBP include a photoelectric conversion unit DPD / PD, a drive circuit 901, a waveform detection unit 902, and a counter 903. The electric charge or current output from the photoelectric conversion unit DPD / PD is detected by the waveform detection unit 902 and then measured by the counter 903. Further, the drive circuit 901 controls the drive of the photoelectric conversion unit DPD / PD based on the electric charge or the current detected by the waveform detection unit 902.
　通常画素ＮＰ及び参照画素ＯＢＰは、垂直制御部９３００及び水平制御部９０１０の制御によってそれぞれ出力が読み出される。読み出された出力は、信号処理部９０２０にて信号処理された後、画像出力として出力される。第２の回路構成に示すように、参照画素ＯＢＰは、通常画素ＮＰの画素アレイの内部に配置されてもよい。 The outputs of the normal pixel NP and the reference pixel OBP are read out under the control of the vertical control unit 9300 and the horizontal control unit 9010, respectively. The read output is signal-processed by the signal processing unit 9020 and then output as an image output. As shown in the second circuit configuration, the reference pixel OBP may be arranged inside the pixel array of the normal pixel NP.
　（第３の回路構成）
　図１５２は、本実施形態に係る光検出装置９００を画素アレイとした場合の第３の回路構成を示すブロック図である。 (Third circuit configuration)
FIG. 152 is a block diagram showing a third circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
　図１５２に示すように、光検出装置９００は、通常画素ＮＰ及び参照画素ＯＢＰを１対１で対応させた画素アレイとして構成されてもよい。 As shown in FIG. 152, the photodetector 900 may be configured as a pixel array in which normal pixels NP and reference pixels OBP have a one-to-one correspondence.
　通常画素ＮＰ及び参照画素ＯＢＰは、それぞれ光電変換部ＤＰＤ／ＰＤ、駆動回路９０１、及び波形検出部９０２を備える。また、通常画素ＮＰ及び参照画素ＯＢＰの対ごとに、通常画素ＮＰ及び参照画素ＯＢＰの各々の波形検出部９０２の検出結果に基づいて入射光子を計測する１つのカウンター９０３が備えられる。 The normal pixel NP and the reference pixel OBP each include a photoelectric conversion unit DPD / PD, a drive circuit 901, and a waveform detection unit 902. Further, for each pair of the normal pixel NP and the reference pixel OBP, one counter 903 for measuring the incident photon based on the detection result of each waveform detection unit 902 of the normal pixel NP and the reference pixel OBP is provided.
　通常画素ＮＰ及び参照画素ＯＢＰは、通常画素ＮＰ及び参照画素ＯＢＰの対ごとに垂直制御部９３００及び水平制御部９０１０の制御によってそれぞれ出力が読み出される。読み出された出力は、信号処理部９０２０にて信号処理された後、画像出力として出力される。 The outputs of the normal pixel NP and the reference pixel OBP are read out for each pair of the normal pixel NP and the reference pixel OBP under the control of the vertical control unit 9300 and the horizontal control unit 9010. The read output is signal-processed by the signal processing unit 9020 and then output as an image output.
　第３の回路構成に示すように、通常画素ＮＰと参照画素ＯＢＰとを１対１対応にて設けることにより、光検出装置９００は、通常画素ＮＰの各々からの出力の精度をより高めることができる。 As shown in the third circuit configuration, the photodetector 900 can further improve the accuracy of the output from each of the normal pixel NPs by providing the normal pixel NP and the reference pixel OBP in a one-to-one correspondence. it can.
　（第４の回路構成）
　図１５３は、本実施形態に係る光検出装置９００を画素アレイとした場合の第４の回路構成を示すブロック図である。 (Fourth circuit configuration)
FIG. 153 is a block diagram showing a fourth circuit configuration when the photodetector 900 according to the present embodiment is a pixel array.
　図１５３に示すように、光検出装置９００は、光源ＬＤと、ＴｏＦ光源制御部９５００とをさらに備え、ＴｏＦセンサとして動作可能であってもよい。 As shown in FIG. 153, the photodetector 900 may further include a light source LD and a ToF light source control unit 9500, and may operate as a ToF sensor.
　具体的には、ＴｏＦ光源制御部９５００は、垂直制御部９３００及び信号処理部９０２０と接続され、ＴｏＦ動作の際に光源ＬＤの発光タイミングを制御する。信号処理部９０２０は、光源ＬＤにおける発光タイミングと、通常画素ＮＰからの出力の遅延時間とに基づいて、対象物で反射した光の飛行時間を算出し、ＴｏＦ出力を出力することができる。したがって、光検出装置９００は、ＴｏＦセンサとしても動作することが可能である。 Specifically, the ToF light source control unit 9500 is connected to the vertical control unit 9300 and the signal processing unit 9020, and controls the light emission timing of the light source LD during the ToF operation. The signal processing unit 9020 can calculate the flight time of the light reflected by the object based on the light emission timing in the light source LD and the delay time of the output from the normal pixel NP, and can output the ToF output. Therefore, the photodetector 900 can also operate as a ToF sensor.
　＜８．適用例＞
　以下では、図１５４～図１６２を参照して、上記にて説明した第１～第７の実施形態に係る光検出装置の適用例について説明する。 <8. Application example>
Hereinafter, application examples of the photodetector according to the first to seventh embodiments described above will be described with reference to FIGS. 154 to 162.
　（積層構成例）
　上述の光検出装置は、図１５４に示す積層構造にて設けられてもよい。具体的には、図１５４に示すように、光検出装置は、入射光を受光し、光電変換を行う受光チップ１１００と、受光チップ１１００からの出力を演算処理するロジックチップ１２００とを積層した構造にて設けられてもよい。受光チップ１１００及びロジックチップ１２００は、ＴＳＶ（Ｔｈｒｏｕｇｈ－Ｓｉｌｉｃｏｎ　Ｖｉａ）又はいわゆるＣｕＣｕ接合などによってチップ間が電気的に接続されていてもよい。 (Example of laminated configuration)
The above-mentioned photodetector may be provided in the laminated structure shown in FIG. 154. Specifically, as shown in FIG. 154, the photodetector has a structure in which a light receiving chip 1100 that receives incident light and performs photoelectric conversion and a logic chip 1200 that performs arithmetic processing on the output from the light receiving chip 1100 are laminated. It may be provided at. The light receiving chip 1100 and the logic chip 1200 may be electrically connected to each other by TSV (Through-Silicon Via) or so-called CuCu bonding.
　上述の光検出装置は、固体撮像素子に適用することが可能である。上述の光検出装置を用いた固体撮像素子１は、図１５５のＡ～Ｃのいずれかの基板構成にて設けられてもよい。 The above-mentioned photodetector can be applied to a solid-state image sensor. The solid-state image pickup device 1 using the above-mentioned photodetector may be provided with any of the substrate configurations A to C in FIG. 155.
　図１５５のＡは、固体撮像素子１を、１枚の半導体基板１１１０と、その下に積層された支持基板１２１０とで構成した例を示している。 FIG. 155A shows an example in which the solid-state image sensor 1 is composed of one semiconductor substrate 1110 and a support substrate 1210 laminated under the semiconductor substrate 1110.
　この場合、上側の半導体基板１１１０には、複数の画素が配列された画素アレイ領域１１５１と、画素アレイ領域１１５１の各画素を制御する制御回路１１５２と、画素信号の信号処理回路を含むロジック回路１１５３とが形成される。 In this case, the upper semiconductor substrate 1110 includes a pixel array region 1151 in which a plurality of pixels are arranged, a control circuit 1152 for controlling each pixel in the pixel array region 1151, and a logic circuit 1153 including a signal processing circuit for pixel signals. And are formed.
　制御回路１１５２には、垂直制御部及び水平制御部などが含まれる。ロジック回路１１５３には、画素信号のＡＤ変換処理などを行うカラム処理部と、画素アレイ領域１１５１の各画素から出力された画素信号の比率から距離を算出する距離算出処理、及びキャリブレーション処理などを行う信号処理部とが含まれる。 The control circuit 1152 includes a vertical control unit, a horizontal control unit, and the like. The logic circuit 1153 includes a column processing unit that performs AD conversion processing of pixel signals, a distance calculation process that calculates a distance from the ratio of pixel signals output from each pixel in the pixel array region 1151, and a calibration process. A signal processing unit to perform is included.
　または、固体撮像素子１は、図１５５のＢに示されるように、画素アレイ領域１１５１及び制御回路１１５２が形成された第１の半導体基板１１２０と、ロジック回路１１５３が形成された第２の半導体基板１２２０とが積層された構成とすることも可能である。なお、第１の半導体基板１１２０、及び第２の半導体基板１２２０は、例えば、貫通ビアやＣｕ－Ｃｕの金属結合により電気的に接続される。 Alternatively, as shown in B of FIG. 155, the solid-state image sensor 1 has a first semiconductor substrate 1120 on which the pixel array region 1151 and the control circuit 1152 are formed, and a second semiconductor substrate on which the logic circuit 1153 is formed. It is also possible to have a configuration in which 1220 and 1220 are laminated. The first semiconductor substrate 1120 and the second semiconductor substrate 1220 are electrically connected by, for example, a through via or a metal bond of Cu—Cu.
　または、固体撮像素子１は、図１５５のＣに示されるように、第１の半導体基板１１３０と、第２の半導体基板１２３０とが積層された構成とすることも可能である。第１の半導体基板１１３０には、画素アレイ領域１１５１のみが設けられ、第２の半導体基板１２３０には、各画素を制御する制御回路、及び画素信号を処理する信号処理回路を１画素単位または複数画素のエリア単位にて設けたエリア制御回路１１５４が設けられる。第１の半導体基板１１３０、及び第２の半導体基板１２３０は、例えば、貫通ビアやＣｕ－Ｃｕの金属結合により電気的に接続される。 Alternatively, as shown in C of FIG. 155, the solid-state image sensor 1 may have a configuration in which the first semiconductor substrate 1130 and the second semiconductor substrate 1230 are laminated. The first semiconductor substrate 1130 is provided with only a pixel array region 1151, and the second semiconductor substrate 1230 is provided with a control circuit for controlling each pixel and a signal processing circuit for processing a pixel signal in units of one pixel or a plurality of. An area control circuit 1154 provided for each pixel area is provided. The first semiconductor substrate 1130 and the second semiconductor substrate 1230 are electrically connected by, for example, through vias or metal bonds of Cu—Cu.
　図１５５のＣの固体撮像素子１のように、１画素単位またはエリア単位で制御回路及び信号処理回路が設けられた構成によれば、固体撮像素子１は、分割制御単位ごとに最適な駆動タイミング及びゲインを設定することができるため、距離又は反射率によらず、最適化された距離情報を取得することができる。また、固体撮像素子１は、画素アレイ領域１１５１の全面ではなく、一部の領域のみを駆動させて、距離情報を算出することもできるため、動作モードに応じて消費電力を抑制することも可能である。 According to the configuration in which the control circuit and the signal processing circuit are provided for each pixel or area as in the solid-state image sensor 1 of C in FIG. And since the gain can be set, the optimized distance information can be acquired regardless of the distance or the reflectance. Further, since the solid-state image sensor 1 can drive only a part of the pixel array region 1151 instead of the entire surface to calculate the distance information, it is possible to suppress the power consumption according to the operation mode. Is.
　（平面レイアウト）
　光検出装置の受光チップ１１００は、図１５６に示すように、画素に対応して行列状に平面配置された受光素子３０を含む画素アレイ領域１１５１を備えていてもよい。 (Plane layout)
As shown in FIG. 156, the light receiving chip 1100 of the photodetector may include a pixel array region 1151 including light receiving elements 30 arranged in a plane in a matrix corresponding to the pixels.
　ロジックチップ１２００は、図１５７に示すように、画素アレイ領域１１５１に対応して設けられた画素回路領域１２６１を備えていてもよい。画素回路領域１２６１には、画素アレイ領域１１５１に含まれる画素の各々を制御する画素回路１２７０が画素ごとに行列状に平面配置されて設けられる。画素回路１２７０の各々は、画素回路領域１２６１の周辺に設けられた垂直制御部１２６２及び水平制御部１２６３にて駆動及び制御される。画素回路１２７０の各々から読み出された画素信号は、信号処理部１２６４にて信号処理されることで画像データとして外部に出力される。 As shown in FIG. 157, the logic chip 1200 may include a pixel circuit area 1261 provided corresponding to the pixel array area 1151. In the pixel circuit area 1261, pixel circuits 1270 for controlling each of the pixels included in the pixel array area 1151 are provided in a planar arrangement in a matrix for each pixel. Each of the pixel circuits 1270 is driven and controlled by a vertical control unit 1262 and a horizontal control unit 1263 provided around the pixel circuit area 1261. The pixel signals read from each of the pixel circuits 1270 are signal-processed by the signal processing unit 1264 and output as image data to the outside.
　また、上述の光検出装置は、図１５８に示す回路構成にて設けられてもよい。 Further, the above-mentioned photodetector may be provided with the circuit configuration shown in FIG. 158.
　具体的には、画素アレイ内の各画素は、例えば、ＤＰＤとして動作可能な受光素子３０と、駆動回路１２７１と、波形検出部１２７２と、カウンター１２７３とを備える。 Specifically, each pixel in the pixel array includes, for example, a light receiving element 30 that can operate as a DPD, a drive circuit 1271, a waveform detection unit 1272, and a counter 1273.
　受光素子３０から出力された電荷又は電流は、波形検出部１２７２にて検出された後、カウンター１２７３に計測される。カウンター１２７３は、例えば、ＴｏＦ用途では「電流立ち上がり時間」を検出する機能を有し、フォトンカウント用途では「電流立ち上がり回数」を検出する機能を有する。また、駆動回路１２７１は、波形検出部１２７２にて検出された電荷又は電流に基づいて、受光素子３０の駆動を制御してもよい。 The charge or current output from the light receiving element 30 is detected by the waveform detection unit 1272 and then measured by the counter 1273. The counter 1273 has, for example, a function of detecting a "current rise time" in a ToF application and a function of detecting a "current rise count" in a photon counting application. Further, the drive circuit 1271 may control the drive of the light receiving element 30 based on the charge or the current detected by the waveform detection unit 1272.
　垂直制御部１２６２及び水平制御部１２６３は、各画素を制御することで、各画素からそれぞれ出力を読み出す。読み出された出力は、信号処理部１２６４にて信号処理された後、画像データとして出力される。 The vertical control unit 1262 and the horizontal control unit 1263 read out the output from each pixel by controlling each pixel. The read output is output as image data after signal processing by the signal processing unit 1264.
　（撮像装置の構成例）
　また、上述した光検出装置は、例えば、図１５９に示した固体撮像装置１０１０Ａに適用可能である。 (Configuration example of imaging device)
Further, the above-mentioned photodetector can be applied to, for example, the solid-state image sensor 1010A shown in FIG. 159.
　固体撮像装置１０１０Ａは、例えばセンサ基板１０２０と回路基板１０３０とが上下に積層された構造を備える。上述した光検出装置は、例えば、センサ部１０２１の受光装置として適用可能である。 The solid-state image sensor 1010A has, for example, a structure in which a sensor substrate 1020 and a circuit board 1030 are vertically laminated. The above-mentioned photodetector can be applied as, for example, a light receiving device of the sensor unit 1021.
　センサ基板１０２０は、例えばセンサ部１０２１と行選択部１０２５とを備える。センサ部１０２１は、行列状に配置された複数のセンサ１０４０を有する。センサ１０４０は、例えばフォトダイオード１０４１、転送トランジスタ（転送ゲートともいう）１０４２、リセットトランジスタ１０４３、増幅トランジスタ１０４４、選択トランジスタ１０４５、浮遊拡散領域部（ＦＤ）１０４６を有する。行選択部１０２５は、回路基板１０３０側から与えられるアドレス信号に基づいて、センサ部１０２１の各センサ１０４０を行単位で選択する。尚、ここでは、行選択部１０２５をセンサ基板１０２０に設けたが、回路基板１０３０に設けることも可能である。 The sensor board 1020 includes, for example, a sensor unit 1021 and a row selection unit 1025. The sensor unit 1021 has a plurality of sensors 1040 arranged in a matrix. The sensor 1040 includes, for example, a photodiode 1041, a transfer transistor (also referred to as a transfer gate) 1042, a reset transistor 1043, an amplification transistor 1044, a selection transistor 1045, and a stray diffusion region (FD) 1046. The row selection unit 1025 selects each sensor 1040 of the sensor unit 1021 in units of rows based on the address signal given from the circuit board 1030 side. Although the row selection unit 1025 is provided on the sensor board 1020 here, it can also be provided on the circuit board 1030.
　回路基板１０３０は、例えば信号処理部１０３１、メモリ部１０３２、データ処理部１０３３、制御部１０３４、電流源１０３５、デコーダ１０３６、行デコーダ１０３７、及びインタフェース（ＩＦ）部１０３８等を備える。また、センサ部１０２１の各センサ１０４０を駆動するセンサ駆動部（図示せず）が設けられている。 The circuit board 1030 includes, for example, a signal processing unit 1031, a memory unit 1032, a data processing unit 1033, a control unit 1034, a current source 1035, a decoder 1036, a row decoder 1037, an interface (IF) unit 1038, and the like. In addition, a sensor drive unit (not shown) for driving each sensor 1040 of the sensor unit 1021 is provided.
　信号処理部１０３１は、例えばセンサ部１０２１の各センサ１０４０からセンサ行毎に読み出されたアナログ信号に対して、センサ列単位で並列（列並列）にデジタル化（ＡＤ変換）を含む所定の信号処理を行うことができる。そして、信号処理部１０３１は、センサ部１０２１の各センサ１０４０から信号線１０２６に読み出されたアナログ信号をデジタル化するアナログ－デジタル変換器（ＡＤ変換器）１０５０を有しており、ＡＤ変換された画像データ（デジタルデータ）をメモリ部１０３２に転送する。 The signal processing unit 1031 receives, for example, a predetermined signal including digitization (AD conversion) in parallel (column parallel) for each sensor row with respect to the analog signal read from each sensor 1040 of the sensor unit 1021 for each sensor row. Processing can be performed. The signal processing unit 1031 has an analog-to-digital converter (AD converter) 1050 that digitizes the analog signal read from each sensor 1040 of the sensor unit 1021 to the signal line 1026, and is subjected to AD conversion. The image data (digital data) is transferred to the memory unit 1032.
　信号線１０２６は、例えば、行列状にセンサ１０４０が配列されたセンサ部１０２１に対して、センサ行毎に行制御線が配線され、センサ列毎に列信号線（垂直信号線）が配線されている。 In the signal line 1026, for example, a row control line is wired for each sensor row and a column signal line (vertical signal line) is wired for each sensor row to the sensor unit 1021 in which the sensors 1040 are arranged in a matrix. There is.
　なお、信号処理部１０３１は、さらに、ＡＤ変換器１０５０でのＡＤ変換の際に用いる参照電圧を生成する参照電圧生成部１０５４を有してもよい。参照電圧生成部１０５４は、例えば、ＤＡ変換器（デジタル－アナログ変換器）を用いて構成することができるが、これに限定されるものではない。 The signal processing unit 1031 may further have a reference voltage generation unit 1054 that generates a reference voltage used for AD conversion by the AD converter 1050. The reference voltage generation unit 1054 can be configured by using, for example, a DA converter (digital-analog converter), but is not limited thereto.
　ＡＤ変換器１０５０は、例えば比較器（コンパレータ）１０５１及びカウンタ部１０５２を有する。比較器１０５１は、センサ部１０２１の各センサ１０４０から信号線１０２６を介して読み出されるアナログ信号を比較入力とし、参照電圧生成部１０５４から供給される参照電圧を基準入力として、両入力を比較する。 The AD converter 1050 has, for example, a comparator 1051 and a counter unit 1052. The comparator 1051 compares both inputs using the analog signal read from each sensor 1040 of the sensor unit 1021 via the signal line 1026 as the comparison input and the reference voltage supplied from the reference voltage generation unit 1054 as the reference input.
　カウンタ部１０５２として、例えば、アップ／ダウンカウンタが用いられる。カウンタ部１０５２には、比較器１０５１に対する参照電圧の供給開始タイミングと同じタイミングでクロックＣＫが与えられる。アップ／ダウンカウンタであるカウンタ部１０５２は、クロックＣＫに同期してダウンカウント、又はアップカウントを行うことで、比較器１０５１の出力パルスのパルス幅の期間（すなわち、比較動作の開始から比較動作の終了までの比較期間）を計測する。そして、カウンタ部１０５２のカウント結果（カウント値）が、アナログ信号をデジタル化したデジタル値（画像データ）となる。 For example, an up / down counter is used as the counter unit 1052. The clock CK is given to the counter unit 1052 at the same timing as the supply start timing of the reference voltage to the comparator 1051. The counter unit 1052, which is an up / down counter, performs down-counting or up-counting in synchronization with the clock CK to perform a period of the pulse width of the output pulse of the comparator 1051 (that is, from the start of the comparison operation to the comparison operation). (Comparison period until the end) is measured. Then, the count result (count value) of the counter unit 1052 becomes a digital value (image data) obtained by digitizing the analog signal.
　データラッチ部１０５５は、ＡＤ変換器１０５０でデジタル化された画像データをラッチする。メモリ部１０３２は、信号処理部１０３１において所定の信号処理が施された画像データを格納する。データ処理部１０３３は、メモリ部１０３２に格納された画像データを所定の順番に読み出し、種々の処理を行い、インタフェース（ＩＦ）１０３８を介してチップ外に出力する。 The data latch unit 1055 latches the image data digitized by the AD converter 1050. The memory unit 1032 stores image data that has undergone predetermined signal processing in the signal processing unit 1031. The data processing unit 1033 reads the image data stored in the memory unit 1032 in a predetermined order, performs various processes, and outputs the image data to the outside of the chip via the interface (IF) 1038.
　制御部１０３４は、例えばチップ外から与えられる水平同期信号ＸＨＳ、垂直同期信号ＸＶＳ、及びマスタークロックＭＣＫ等の基準信号に基づいて、センサ駆動部（図示せず）、メモリ部１０３２、及びデータ処理部１０３３等の信号処理部１０３１の各動作の制御を行う。このとき、制御部１０３４は、センサ基板１０２０側の回路（行選択部１０２５やセンサ部１０２１）と、回路基板１０３０側の信号処理部１０３１（メモリ部１０３２、データ処理部１０３３等）との同期を取りつつ、制御を行う。 The control unit 1034 is a sensor drive unit (not shown), a memory unit 1032, and a data processing unit based on reference signals such as a horizontal synchronization signal XHS, a vertical synchronization signal XVS, and a master clock MCK given from outside the chip. It controls each operation of the signal processing unit 1031 such as 1033. At this time, the control unit 1034 synchronizes the circuit on the sensor board 1020 side (row selection unit 1025 and sensor unit 1021) with the signal processing unit 1031 (memory unit 1032, data processing unit 1033, etc.) on the circuit board 1030 side. Control while taking.
　電流源１０３５には、例えばセンサ部１０２１の各センサ１０４０からセンサ列毎にアナログ信号が読み出される信号線１０２６の各々が接続されている。電流源１０３５は、例えば、信号線１０２６に所定の電流を供給するように、ゲート電位が一定電位にバイアスされたＭＯＳトランジスタを含む負荷ＭＯＳ回路構成を有する。このような負荷ＭＯＳ回路を含む電流源１０３５は、選択された行に含まれるセンサ１０４０の増幅トランジスタ１０４４に定電流を供給することにより、増幅トランジスタ１０４４をソースフォロアとして動作させる。 The current source 1035 is connected to, for example, each of the signal lines 1026 from which analog signals are read out for each sensor row from each sensor 1040 of the sensor unit 1021. The current source 1035 has, for example, a load MOS circuit configuration including a MOS transistor whose gate potential is biased to a constant potential so as to supply a predetermined current to the signal line 1026. The current source 1035 including such a load MOS circuit operates the amplification transistor 1044 as a source follower by supplying a constant current to the amplification transistor 1044 of the sensor 1040 included in the selected row.
　デコーダ１０３６は、制御部１０３４の制御に基づいて、センサ部１０２１の各センサ１０４０を行単位で選択する際に、選択行のアドレスを指定するアドレス信号を行選択部１０２５に対して与える。行デコーダ１０３７は、制御部１０３４の制御に基づいて、メモリ部１０３２に画像データを書き込んだり、メモリ部１０３２から画像データを読み出したりする際の行アドレスを指定する。 The decoder 1036 gives an address signal for designating the address of the selected row to the row selection unit 1025 when selecting each sensor 1040 of the sensor unit 1021 in line units based on the control of the control unit 1034. The row decoder 1037 specifies a row address for writing image data to the memory unit 1032 and reading image data from the memory unit 1032 based on the control of the control unit 1034.
　センサ基板１０２０と回路基板１０３０とは、例えば半導体基板を貫通するＴＳＶ（Ｔｈｒｏｕｇｈ－Ｓｉｌｉｃｏｎ　Ｖｉａ）などの接続部を介して電気的に接続される。ＴＳＶを用いた接続には、例えば、センサ基板１０２０に設けられたＴＳＶと、センサ基板１０２０から回路基板１０３０にかけて設けられたＴＳＶとの２つのＴＳＶをチップ外表で接続する、いわゆるＴｗｉｎ　ＴＳＶ方式、又はセンサ基板１０２０から回路基板１０３０まで貫通するＴＳＶで両者を接続する、いわゆるＳｈａｒｅｄ　ＴＳＶ方式などを用いることができる。 The sensor substrate 1020 and the circuit board 1030 are electrically connected via a connection portion such as a TSV (Through Silicon Via) that penetrates the semiconductor substrate. For connection using TSV, for example, a so-called Twin TSV method in which two TSVs, a TSV provided on the sensor board 1020 and a TSV provided from the sensor board 1020 to the circuit board 1030, are connected on the outer surface of the chip, or A so-called Shared TSV method or the like in which both are connected by a TSV penetrating from the sensor board 1020 to the circuit board 1030 can be used.
　また、センサ基板１０２０と回路基板１０３０とは、例えば互いの接合面に形成された電極パッド同士を貼り合わせる、いわゆる金属接合などの接続部を介して電気的に接続される。このとき、電極パッドは銅などの金属で形成され、Ｃｕ－Ｃｕ接合ともいう。その他、センサ基板１０２０と回路基板１０３０との接続部には、バンプ接合などを用いることもできる。 Further, the sensor board 1020 and the circuit board 1030 are electrically connected via a connection portion such as a so-called metal joint in which electrode pads formed on the joint surfaces of each other are bonded to each other. At this time, the electrode pad is made of a metal such as copper and is also called a Cu-Cu bond. In addition, bump bonding or the like can be used for the connection portion between the sensor board 1020 and the circuit board 1030.
　上述した光検出装置が適用される固体撮像装置は、例えば、図１６０Ａ及び図１６０Ｂに示す断面構造を備えていてもよい。図１６０Ａは、有効画素における断面構成例であり、図１６０Ｂは、遮光画素における断面構成例である。 The solid-state image sensor to which the above-mentioned photodetector is applied may have, for example, the cross-sectional structure shown in FIGS. 160A and 160B. FIG. 160A is an example of a cross-sectional configuration of an effective pixel, and FIG. 160B is an example of a cross-sectional configuration of a light-shielding pixel.
　図１６０Ａ及び図１６０Ｂに示すように、光検出装置が適用される固体撮像装置１３００は、下基板１３２０と上基板１３１０とを積層した積層構造にて設けられる。下基板１３２０と上基板１３１０とは、金属電極同士を接合した接続構造を含むＣｕＣｕ接合部１３７０にて電気的に接続される。 As shown in FIGS. 160A and 160B, the solid-state image sensor 1300 to which the photodetector is applied is provided with a laminated structure in which the lower substrate 1320 and the upper substrate 1310 are laminated. The lower substrate 1320 and the upper substrate 1310 are electrically connected by a CuCu joint portion 1370 including a connection structure in which metal electrodes are bonded to each other.
　下基板１３２０は、信号読出回路及び信号処理回路などのロジック回路、並びにメモリ回路を含む回路部１３８０を備える。 The lower board 1320 includes a logic circuit such as a signal reading circuit and a signal processing circuit, and a circuit unit 1380 including a memory circuit.
　上基板１３１０は、配線部１３６０と、画素部１３５０と、裏面電極部１３４０と、光入射部１３３０とを備える。上基板１３１０は、下基板１３２０との積層面側から配線部１３６０、画素部１３５０、裏面電極部１３４０、及び光入射部１３３０を順に積層することで設けられる。 The upper substrate 1310 includes a wiring portion 1360, a pixel portion 1350, a back surface electrode portion 1340, and a light incident portion 1330. The upper substrate 1310 is provided by laminating the wiring portion 1360, the pixel portion 1350, the back surface electrode portion 1340, and the light incident portion 1330 in this order from the laminated surface side with the lower substrate 1320.
　配線部１３６０は、配線層１３６１及び層間絶縁膜１３６２を含む。配線部１３６０は、ＣｕＣｕ接合部１３７０を介して、画素部１３５０に含まれる各画素からの出力を回路部１３８０に伝送する。 The wiring unit 1360 includes a wiring layer 1361 and an interlayer insulating film 1362. The wiring unit 1360 transmits the output from each pixel included in the pixel unit 1350 to the circuit unit 1380 via the CuCu junction 1370.
　画素部１３５０は、第１導電型（Ｎ＋）の第１領域１３５１、第２導電型（Ｐ＋）の第２領域１３５２、第３導電型（ｉ）の第３領域１３５３、及び画素間を電気的に分離する画素分離層１３５５を含む。画素部１３５０は、固体撮像装置１３００に入射した光を信号に変換し、配線部１３６０に出力する。 The pixel unit 1350 electrically connects the first region 1351 of the first conductive type (N +), the second region 1352 of the second conductive type (P +), the third region 1353 of the third conductive type (i), and the pixels. Includes a pixel separation layer 1355 to separate into. The pixel unit 1350 converts the light incident on the solid-state image sensor 1300 into a signal and outputs it to the wiring unit 1360.
　裏面電極部１３４０は、第１領域１３５１に電気的に接続される第１電極１３４２、及び第１電極１３４２を埋め込んで平坦化する絶縁膜１３４１を含む。図１６０Ａに示す有効画素では、第１電極１３４２は、画素の光の入射面を開口して設けられる。一方、図１６０Ｂに示す遮光画素（オプティカルブラック画素、上述した参照画素ＯＢＰに対応）では、第１電極１３４２は、画素への光の入射を遮るために、画素の光の入射面を覆うように設けられる。 The back electrode portion 1340 includes a first electrode 1342 electrically connected to the first region 1351 and an insulating film 1341 that embeds and flattens the first electrode 1342. In the effective pixel shown in FIG. 160A, the first electrode 1342 is provided by opening the incident surface of the light of the pixel. On the other hand, in the light-shielding pixel (optical black pixel, corresponding to the reference pixel OBP described above) shown in FIG. 160B, the first electrode 1342 covers the incident surface of the light of the pixel in order to block the light incident on the pixel. It is provided.
　光入射部１３３０は、画素部１３５０に入射する光の波長帯域を画素ごとに制御するカラーフィルタ１３３２、及び入射光を画素中心に集光するオンチップレンズ１３３１を含む。 The light incident unit 1330 includes a color filter 1332 that controls the wavelength band of light incident on the pixel unit 1350 for each pixel, and an on-chip lens 1331 that collects the incident light at the center of the pixel.
　なお、ＴｏＦ又はセンシングなどの固体撮像装置１３００の用途によっては、カラーフィルタ１３３２及びオンチップレンズ１３３１を設けるか、設けないかは任意で選択されてもよい。 Depending on the application of the solid-state image sensor 1300 such as ToF or sensing, it may be arbitrarily selected whether or not the color filter 1332 and the on-chip lens 1331 are provided.
　また、回路部１３８０に含まれる一部の回路は、上基板１３１０に設けられてもよい。もしくは、回路部１３８０に含まれるすべての回路は、画素部１３５０と同一の基板に設けられてもよい。このような場合、回路部１３８０は、画素部１３５０が配列された画素領域の周辺領域に設けられる。 Further, some circuits included in the circuit unit 1380 may be provided on the upper board 1310. Alternatively, all the circuits included in the circuit unit 1380 may be provided on the same substrate as the pixel unit 1350. In such a case, the circuit unit 1380 is provided in the peripheral region of the pixel region in which the pixel unit 1350 is arranged.
　（距離画像センサの構成例）
　図１６１は、上述の光検出装置を用いたセンサチップを利用した電子機器である距離画像センサの構成例を示すブロック図である。 (Configuration example of distance image sensor)
FIG. 161 is a block diagram showing a configuration example of a distance image sensor which is an electronic device using a sensor chip using the above-mentioned photodetector.
　図１６１に示すように、距離画像センサ２２０１は、光学系２２０２、センサチップ２２０３、画像処理回路２２０４、モニタ２２０５、およびメモリ２２０６を備えて構成される。そして、距離画像センサ２２０１は、光源装置２２１１から被写体に向かって投光された後、被写体の表面で反射された光（変調光やパルス光）を受光することにより、被写体までの距離応じた距離画像を取得することができる。 As shown in FIG. 161, the distance image sensor 2201 includes an optical system 2202, a sensor chip 2203, an image processing circuit 2204, a monitor 2205, and a memory 2206. Then, the distance image sensor 2201 receives the light (modulated light or pulsed light) reflected on the surface of the subject after the light is projected from the light source device 2211 toward the subject, so that the distance to the subject corresponds to the distance. Images can be acquired.
　光学系２２０２は、１枚または複数枚のレンズを有して構成され、被写体からの像光（入射光）をセンサチップ２２０３に導き、センサチップ２２０３の受光面（センサ部）に結像させる。 The optical system 2202 is configured to have one or a plurality of lenses, guides the image light (incident light) from the subject to the sensor chip 2203, and forms an image on the light receiving surface (sensor unit) of the sensor chip 2203.
　センサチップ２２０３としては、上述した光検出装置が適用され得る。センサチップ２２０３から出力される受光信号から求められる距離を示す距離信号と、光源装置２２１１から出力される発光タイミング信号とは、画像処理回路２２０４に供給される。 The above-mentioned photodetector can be applied to the sensor chip 2203. The distance signal indicating the distance obtained from the light receiving signal output from the sensor chip 2203 and the light emission timing signal output from the light source device 2211 are supplied to the image processing circuit 2204.
　画像処理回路２２０４は、光源装置２２１１から供給された発光タイミング信号と、センサチップ２２０３から供給された距離信号とに基づいて、距離画像を構築する画像処理を行う。その画像処理により得られた距離画像（画像データ）は、モニタ２２０５に供給されて表示されたり、メモリ２２０６に供給されて記憶（記録）されたりする。 The image processing circuit 2204 performs image processing for constructing a distance image based on the light emission timing signal supplied from the light source device 2211 and the distance signal supplied from the sensor chip 2203. The distance image (image data) obtained by the image processing is supplied to the monitor 2205 and displayed, or is supplied to the memory 2206 and stored (recorded).
　このように構成されている距離画像センサ２２０１では、上述した光検出装置を適用することで、ＤＰＤ画素の特性向上に伴って、例えば、より正確な距離画像を取得することができる。 In the distance image sensor 2201 configured in this way, by applying the above-mentioned photodetector, for example, a more accurate distance image can be acquired as the characteristics of the DPD pixel are improved.
　（測距モジュールの構成例）
　図１６２は、光検出装置を用いて測距情報を出力する測距モジュールの構成例を示すブロック図である。 (Configuration example of ranging module)
FIG. 162 is a block diagram showing a configuration example of a distance measuring module that outputs distance measurement information using a photodetector.
　測距モジュール１０００は、発光部１０１１、発光制御部１０１２、および受光部１０１３を備える。 The ranging module 1000 includes a light emitting unit 1011, a light emitting control unit 1012, and a light receiving unit 1013.
　発光部１０１１は、所定波長の光を発する光源を有し、周期的に明るさが変動する照射光を発して物体に照射する。例えば、発光部１０１１は、光源として、波長が７８０ｎｍ～１０００ｎｍの範囲の赤外光を発する発光ダイオードを有し、発光制御部１０１２から供給される矩形波の発光制御信号ＣＬＫｐに同期して、照射光を発する。 The light emitting unit 1011 has a light source that emits light having a predetermined wavelength, and emits irradiation light whose brightness fluctuates periodically to irradiate an object. For example, the light emitting unit 1011 has a light emitting diode that emits infrared light having a wavelength in the range of 780 nm to 1000 nm as a light source, and emits light in synchronization with the light emission control signal CLKp of a square wave supplied from the light emitting control unit 1012. It emits light.
　なお、発光制御信号ＣＬＫｐは、周期信号であれば、矩形波に限定されない。例えば、発光制御信号ＣＬＫｐは、サイン波であってもよい。 Note that the emission control signal CLKp is not limited to a square wave as long as it is a periodic signal. For example, the light emission control signal CLKp may be a sine wave.
　発光制御部１０１２は、発光制御信号ＣＬＫｐを発光部１０１１および受光部１０１３に供給し、照射光の照射タイミングを制御する。この発光制御信号ＣＬＫｐの周波数は、例えば、２０メガヘルツ（ＭＨｚ）である。なお、発光制御信号ＣＬＫｐの周波数は、２０メガヘルツ（ＭＨｚ）に限定されず、５メガヘルツ（ＭＨｚ）などであってもよい。 The light emission control unit 1012 supplies the light emission control signal CLKp to the light emitting unit 1011 and the light receiving unit 1013, and controls the irradiation timing of the irradiation light. The frequency of the light emission control signal CLKp is, for example, 20 megahertz (MHz). The frequency of the light emission control signal CLKp is not limited to 20 MHz (MHz) and may be 5 MHz (MHz) or the like.
　受光部１０１３は、物体から反射した反射光を受光し、受光結果に応じて距離情報を画素ごとに算出し、物体までの距離を画素ごとに階調値で表したデプス画像を生成して、出力する。 The light receiving unit 1013 receives the reflected light reflected from the object, calculates the distance information for each pixel according to the light receiving result, and generates a depth image in which the distance to the object is represented by a gradation value for each pixel. Output.
　受光部１０１３には、上述した光検出装置が用いられ、受光部１０１３としての固体撮像素子は、例えば、発光制御信号ＣＬＫｐに基づいて、画素アレイ部の各画素で検出された信号強度から、距離情報を画素ごとに算出する。 The above-mentioned photodetector is used for the light receiving unit 1013, and the solid-state image sensor as the light receiving unit 1013 is, for example, a distance from the signal intensity detected in each pixel of the pixel array unit based on the light emission control signal CLKp. Information is calculated for each pixel.
　以上のように、例えば間接ＴｏＦ方式により被写体までの距離情報を求めて出力する測距モジュール１０００の受光部１０１３として、上述の光検出装置を組み込むことができる。測距モジュール１０００の受光部１０１３として、上述した光検出装置を採用することにより、測距モジュール１０００としての測距特性を向上させることができる。 As described above, the above-mentioned photodetector can be incorporated as the light receiving unit 1013 of the distance measuring module 1000 that obtains and outputs the distance information to the subject by, for example, the indirect ToF method. By adopting the above-mentioned photodetector as the light receiving unit 1013 of the distance measuring module 1000, the distance measuring characteristics of the distance measuring module 1000 can be improved.
　以上のように、上述した光検出装置を測距モジュールの構成とすることで、測距特性を向上させることができる。 As described above, by configuring the above-mentioned photodetector as a distance measuring module, the distance measuring characteristics can be improved.
　＜９．付記＞
　上記では、光検出装置において、主に信号キャリアとして電子を用いる例について説明したが、信号キャリアとして正孔を用いることも可能である。 <9. Addendum>
In the above, an example in which electrons are mainly used as signal carriers in the photodetector has been described, but holes can also be used as signal carriers.
　ここで、図１６３Ａにて信号キャリアとして電子を用いる場合の光検出装置１０の構成を示し、図１６３Ｂにて信号キャリアとして正孔を用いる場合の光検出装置１０Ａの構成を示す。 Here, FIG. 163A shows the configuration of the photodetector 10 when electrons are used as the signal carrier, and FIG. 163B shows the configuration of the photodetector 10A when holes are used as the signal carrier.
　図１６３Ａに示すように、光検出装置１０は、例えば、Ｎ＋型の第１領域１１と、Ｐ＋型の第２領域１２と、ｉ型の第３領域１３と、第１領域１１と電気的に接続された第１電極２１と、画素間を分離する画素分離層１５と、第２領域１２と電気的に接続された第２電極２２と、第３領域１３のポテンシャルを制御する制御ゲート２５及びゲート絶縁膜２６とを備える。 As shown in FIG. 163A, the photodetector 10 electrically includes, for example, an N + type first region 11, a P + type second region 12, an i-type third region 13, and a first region 11. The connected first electrode 21, the pixel separation layer 15 that separates the pixels, the second electrode 22 that is electrically connected to the second region 12, the control gate 25 that controls the potential of the third region 13, and the control gate 25. It includes a gate insulating film 26.
　図１６３Ａに示す光検出装置１０では、信号キャリアを検出するために設けられた第２領域１２がＰ＋型半導体領域として構成され、基板内に電界を発生させるために設けられた第１領域１１がＮ＋半導体領域として構成される。これにより、光検出装置１０は、第２領域１２にて信号キャリアとして電子を検出することができる。 In the photodetector 10 shown in FIG. 163A, the second region 12 provided for detecting the signal carrier is configured as a P + type semiconductor region, and the first region 11 provided for generating an electric field in the substrate is provided. It is configured as an N + semiconductor region. As a result, the photodetector 10 can detect electrons as signal carriers in the second region 12.
　一方、図１６３Ｂに示すように、光検出装置１０Ａは、例えば、Ｐ＋型の第１領域１１Ａと、Ｎ＋型の第２領域１２Ａと、ｉ型の第３領域１３と、第１領域１１と電気的に接続された第１電極２１と、画素間を分離する画素分離層１５と、第２領域１２と電気的に接続された第２電極２２と、第３領域１３のポテンシャルを制御する制御ゲート２５及びゲート絶縁膜２６とを備える。 On the other hand, as shown in FIG. 163B, the photodetector 10A has, for example, a P + type first region 11A, an N + type second region 12A, an i type third region 13, and a first region 11 and electricity. A control gate that controls the potential of the first electrode 21, the pixel separation layer 15 that separates the pixels, the second electrode 22 that is electrically connected to the second region 12, and the third region 13. 25 and a gate insulating film 26 are provided.
　図１６３Ｂに示す光検出装置１０Ａでは、信号キャリアを検出するために設けられた第２領域１２ＡがＮ＋型半導体領域として構成され、基板内に電界を発生させるために設けられた第１領域１１ＡがＰ＋半導体領域として構成される。これにより、光検出装置１０Ａは、第２領域１２Ａにて信号キャリアとして正孔を検出することができる。 In the photodetector 10A shown in FIG. 163B, the second region 12A provided for detecting the signal carrier is configured as an N + type semiconductor region, and the first region 11A provided for generating an electric field in the substrate is provided. It is configured as a P + semiconductor region. As a result, the photodetector 10A can detect holes as signal carriers in the second region 12A.
　本開示に係る技術は、イメージング及びセンシング用途の両方が考えられるイメージセンサ等の半導体装置に関するものである。具体的には、フォトンカウント、ＴｏＦ（Ｔｉｍｅ－ｏｆ－Ｆｌｉｇｈｔ）等の動作が可能な光検出装置に関するものである。 The technology according to the present disclosure relates to semiconductor devices such as image sensors that can be used for both imaging and sensing. Specifically, the present invention relates to a photodetector capable of operating photon counting, ToF (Time-of-Flight), and the like.
　本開示に係る光検出装置は、裏面照射型ＣＭＯＳイメージセンサとして構成されることで、光入射面側の配線を削減し、受光部の開口率を増加させることができる。これにより、光検出装置のセンサの感度が向上する。 By configuring the photodetector according to the present disclosure as a back-illuminated CMOS image sensor, it is possible to reduce the wiring on the light incident surface side and increase the aperture ratio of the light receiving portion. This improves the sensitivity of the sensor of the photodetector.
　なお、本開示に係る技術では、以上において説明した実施形態を適宜組み合わせることも可能である。また、例えば画素の感度やセンサの動作モード等のどの特性を優先するかに応じて、画素内に設ける電荷検出部（第１領域又は第２領域など）及び電圧印加部（カソード電極又はアノード電極など）の個数及び配置位置、電荷検出部の形状及び配置位置、アノード電極、カソード電極、画素トランジスタ、ロジック回路部、及びメモリ回路部の一部又は全部を複数画素で共有構造とするか否か、オンチップレンズ及びカラーフィルタの有無、画素間遮光部の有無、分離領域の有無、画素間遮光部又は分離領域の形状及び深さ、オンチップレンズ及び基板の厚み、基板の種類及び膜設計、入射面へのバイアスの有無、並びに反射部材の有無などの様々な技術的特徴を適切に選択することが可能である。 In the technique according to the present disclosure, it is also possible to appropriately combine the embodiments described above. Further, for example, a charge detection unit (first region or second region, etc.) and a voltage application unit (cathode electrode or anode electrode) provided in the pixel are provided in the pixel depending on which characteristic such as the sensitivity of the pixel or the operation mode of the sensor is prioritized. Whether or not a part or all of the number and arrangement position, the shape and arrangement position of the charge detection unit, the anode electrode, the cathode electrode, the pixel transistor, the logic circuit unit, and the memory circuit unit are shared by a plurality of pixels. , Presence / absence of on-chip lens and color filter, presence / absence of inter-pixel light-shielding part, presence / absence of separation area, shape and depth of inter-pixel light-shielding part or separation area, thickness of on-chip lens and substrate, substrate type and film design, It is possible to appropriately select various technical features such as the presence / absence of a bias on the incident surface and the presence / absence of a reflective member.
　以上、第１～第７の実施形態、及び変形例を挙げて、本開示にかかる技術を説明した。ただし、本開示にかかる技術は、上記実施の形態等に限定されるわけではなく、種々の変形が可能である。 The techniques related to the present disclosure have been described above with reference to the first to seventh embodiments and modified examples. However, the technique according to the present disclosure is not limited to the above-described embodiment and the like, and various modifications can be made.
　さらに、各実施形態で説明した構成および動作の全てが本開示の構成および動作として必須であるとは限らない。たとえば、各実施形態における構成要素のうち、本開示の最上位概念を示す独立請求項に記載されていない構成要素は、任意の構成要素として理解されるべきである。 Furthermore, not all of the configurations and operations described in each embodiment are essential as the configurations and operations of the present disclosure. For example, among the components in each embodiment, the components not described in the independent claims indicating the highest level concept of the present disclosure should be understood as arbitrary components.
　本明細書および添付の特許請求の範囲全体で使用される用語は、「限定的でない」用語と解釈されるべきである。例えば、「含む」又は「含まれる」という用語は、「含まれるとして記載された様態に限定されない」と解釈されるべきである。「有する」という用語は、「有するとして記載された様態に限定されない」と解釈されるべきである。 The terms used throughout this specification and the appended claims should be construed as "non-limiting" terms. For example, the term "included" or "included" should be construed as "not limited to the mode described as included." The term "have" should be construed as "not limited to the mode described as having."
　本明細書で使用した用語には、単に説明の便宜のために用いており、構成及び動作を限定する目的で使用したわけではない用語が含まれる。たとえば、「右」、「左」、「上」、「下」などの用語は、参照している図面上での方向を示しているにすぎない。また、「内側」、「外側」という用語は、それぞれ、注目要素の中心に向かう方向、注目要素の中心から離れる方向を示しているにすぎない。これらに類似する用語や同様の趣旨の用語についても同様である。 The terms used in this specification include terms used solely for convenience of explanation and not used for the purpose of limiting the configuration and operation. For example, terms such as "right," "left," "top," and "bottom" only indicate the orientation on the referenced drawing. Further, the terms "inside" and "outside" merely indicate the direction toward the center of the attention element and the direction away from the center of the attention element, respectively. The same applies to terms similar to these and terms having a similar purpose.
　なお、本開示にかかる技術は、以下のような構成を取ることも可能である。以下の構成を備える本開示にかかる技術によれば、第１電極を半導体基板の第２面から半導体基板の厚み方向に延在させて底面にて第１領域と電気的に接続させ、第２電極を半導体基板の第２面側から第２領域と電気的に接続させることができる。よって、本実施形態に係る光検出装置は、光入射面の開口率を向上させることができるため、入射光の検出特性を向上させることができる。本開示にかかる技術が奏する効果は、ここに記載された効果に必ずしも限定されるわけではなく、本開示中に記載されたいずれの効果であってもよい。
（１）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板の第１面側に設けられた第１導電型の第１領域と、
　前記半導体基板の前記第１面と反対の第２面側に設けられた第２導電型の第２領域と、
　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
　前記第２面から前記半導体基板の厚み方向に延在し、底面にて前記第１領域と電気的に接続する第１電極と、
　前記第１電極の側面に設けられた絶縁性の画素分離層と、
　前記第２面側から前記第２領域と電気的に接続する第２電極と
を備える、光検出装置。
（２）
　前記第１電極の底面から前記第１面まで延在し、前記第１電極よりも幅が小さい上部第１電極と、
　前記上部第１電極の側面に設けられた絶縁性の上部画素分離層と
をさらに備える、上記（１）に記載の光検出装置。
（３）
　前記第１電極及び前記画素分離層は、隣接する前記光電変換部の間に設けられる、上記（１）又は（２）に記載の光検出装置。
（４）
　前記第１電極は、隣接する前記光電変換部の各々の前記第１領域と前記底面にて電気的に接続する、上記（３）に記載の光検出装置。
（５）
　前記第１電極の前記第２面からの形成深さは、前記第２領域の前記第２面からの形成深さよりも深い、上記（１）～（４）のいずれか一項に記載の光検出装置。
（６）
　前記半導体基板の前記第２面にゲート絶縁膜を介して設けられたゲート電極をさらに備える、上記（１）～（５）のいずれか一項に記載の光検出装置。
（７）
　前記ゲート電極は、前記半導体基板を厚み方向に掘り込んで設けられた縦型ゲート電極である、上記（６）に記載の光検出装置。
（８）
　前記半導体基板の前記第２面側に、前記第２領域と絶縁層を挟んで設けられ、電位を制御可能な前記第１導電型のポテンシャル制御領域をさらに備える、上記（１）～（７）のいずれか一項に記載の光検出装置。
（９）
　前記半導体基板の厚み方向における前記第１領域及び前記第２領域の形成深さは、前記光電変換部ごとにそれぞれ異なる、上記（１）～（８）のいずれか一項に記載の光検出装置。
（１０）
　前記半導体基板の前記第２面に積層された多層配線層をさらに備える、上記（１）～（９）のいずれか一項に記載の光検出装置。
（１１）
　前記多層配線層は、前記半導体基板の面内方向に広がる遮光構造を含む、上記（１０）に記載の光検出装置。
（１２）
　前記半導体基板の前記第１面に設けられ、前記入射光を散乱又は回折させる凹凸構造をさらに備える、上記（１）～（１１）のいずれか一項に記載の光検出装置。
（１３）
　前記半導体基板の前記第２面側に設けられた前記第２導電型のフローティングディフュージョン領域と、
　前記第２領域と、前記フローティングディフュージョン領域との間に設けられ、前記第２領域から前記フローティングディフュージョン領域への電荷の転送を制御する転送ゲートトランジスタと
をさらに備える、上記（１）～（１２）のいずれか一項に記載の光検出装置。
（１４）
　前記第２領域を挟んで前記フローティングディフュージョン領域と反対側に設けられた前記第２導電型のオーバーフロードレイン領域と、
　前記第２領域と、前記オーバーフロードレイン領域との間に設けられ、前記第２領域から前記オーバーフロードレイン領域への電荷の転送を制御するオーバーフローゲートトランジスタと
をさらに備える、上記（１３）に記載の光検出装置。
（１５）
　前記半導体基板と、絶縁性材料との界面に設けられたピニング層をさらに備え、
　前記ピニング層は、帯電性を有する層、又は前記第２導電型の層である、上記（１）～（１４）のいずれか一項に記載の光検出装置。
（１６）
　前記第２領域よりも前記第１面側に、前記第２領域と接して設けられた前記第１導電型の第４領域と、
　前記第２領域と前記第４領域との接合面を前記半導体基板の面内方向にて囲む絶縁層と
をさらに備える、上記（１）～（１５）のいずれか一項に記載の光検出装置。
（１７）
　前記第２領域よりも前記第１面側に、前記第２領域と接して設けられた前記第１導電型の第４領域と、
　前記第１領域よりも前記第２面側に、前記第１領域と接して設けられた前記第２導電型の第５領域と
をさらに備える、上記（１）～（１５）のいずれか一項に記載の光検出装置。
（１８）
　複数の前記光電変換部は、前記入射光の入射面に遮光部が設けられた参照画素の前記光電変換部と、前記遮光部が設けられない通常画素の前記光電変換部とを含む、上記（１）～（１７）のいずれか一項に記載の光検出装置。
（１９）
　前記参照画素は、前記通常画素と隣接して設けられる、上記（１８）に記載の光検出装置。
（２０）
　前記第１電極はカソード電極であり、前記第２電極はアノード電極である、上記（１）～（１９）のいずれか一項に記載の光検出装置。
 
（３０）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板の第１面側に設けられた第１導電型の第１領域と、
　前記半導体基板の前記第１面と反対の第２面側に設けられた第２導電型の第２領域と、
　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
　前記第２面から前記半導体基板の厚み方向に延在する第３電極及び第４電極と、
　前記第３電極及び前記第４電極の各々の底面から前記第１面まで延在し、前記第３電極及び前記第４電極よりも幅が小さい複数の貫通絶縁層と、
　前記第３電極及び前記第４電極の各々の側面に設けられた絶縁性の画素分離層と、
　前記貫通絶縁層から露出された前記第３電極の底面と電気的に接続する前記第２導電型の電位制御領域と、
　前記貫通絶縁層から露出された前記第４電極の底面と電気的に接続する前記第１導電型のリセット領域と、
　前記第１面側から前記第１領域と電気的に接続する第１電極と、
　前記第２面側から前記第２領域と電気的に接続する第２電極と
を備える、光検出装置。
（３１）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板に設けられ、第１電極と電気的に接続された第１導電型の第１領域と、
　前記第１領域と互いに離隔されて前記半導体基板に設けられ、第２電極と電気的に接続された第２導電型の第２領域と、
　前記第２領域と接して前記半導体基板の深さ方向に設けられた前記第１導電型の第４領域と、
　前記第２領域と前記第４領域との接合面を前記半導体基板の面内方向にて囲む絶縁層と、
　前記半導体基板に設けられ、入射光を吸収する第３導電型の第３領域と、
を備える、光検出装置。
（３２）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板に設けられ、第１電極と電気的に接続された第１導電型の第１領域と、
　前記第１領域と互いに離隔されて前記半導体基板に設けられ、第２電極と電気的に接続された第２導電型の第２領域と、
　前記第１領域に対して前記第２領域が設けられた側に、前記第１領域と接して設けられた前記第２導電型の第５領域と、
　前記第２領域に対して前記第１領域が設けられた側に、前記第２領域と接して設けられた前記第１導電型の第４領域と、
　前記半導体基板の前記第４領域と前記第５領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
を備える、光検出装置。
（３３）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板に設けられ、第１電極と電気的に接続された第１導電型の第１領域と、
　前記第１領域と互いに離隔されて前記半導体基板に設けられ、第２電極と電気的に接続された第２導電型の第２領域と、
　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
　前記半導体基板の前記第３領域に対応する表面と、絶縁性材料との界面に帯電性を有する層、又は前記第２導電型の層として設けられたピニング層と
を備える、光検出装置。
（３４）
　半導体基板に設けられた複数の光電変換部
を備え、
　前記光電変換部は、
　前記半導体基板の第１面側に設けられ、第１電極と電気的に接続された第１導電型の第１領域と、
　前記半導体基板の前記第１面と反対の第２面側に設けられ、第２電極と電気的に接続された第２導電型の第２領域と、
　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
　前記半導体基板の前記第２面側に設けられた前記第２導電型のフローティングディフュージョン領域と、
　前記第２領域と、前記フローティングディフュージョン領域との間に設けられ、前記第２領域から前記フローティングディフュージョン領域への電荷の転送を制御する転送ゲートトランジスタと
を備える、光検出装置。
（３５）
　半導体基板に設けられ、第１電極と電気的に接続された第１導電型の第１領域と、
　前記第１領域と互いに離隔されて前記半導体基板に設けられ、第２電極と電気的に接続された第２導電型の第２領域と、
　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と
を含む複数の光電変換部を備え、
　複数の前記光電変換部は、前記入射光の入射面に遮光部が設けられた参照画素の前記光電変換部と、前記遮光部が設けられない通常画素の前記光電変換部とを含み、
　前記参照画素は、前記通常画素と隣接して設けられる、光検出装置。 The technology according to the present disclosure can also have the following configuration. According to the technique according to the present disclosure having the following configuration, the first electrode extends from the second surface of the semiconductor substrate in the thickness direction of the semiconductor substrate and is electrically connected to the first region on the bottom surface to form a second electrode. The electrodes can be electrically connected to the second region from the second surface side of the semiconductor substrate. Therefore, the photodetector according to the present embodiment can improve the aperture ratio of the light incident surface, so that the detection characteristics of the incident light can be improved. The effect of the technique according to the present disclosure is not necessarily limited to the effects described herein, and may be any of the effects described in the present disclosure.
(1)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
The first region of the first conductive type provided on the first surface side of the semiconductor substrate and
A second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and
A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and
A first electrode extending from the second surface in the thickness direction of the semiconductor substrate and electrically connecting to the first region on the bottom surface,
An insulating pixel separation layer provided on the side surface of the first electrode and
A photodetector comprising a second electrode that is electrically connected to the second region from the second surface side.
(2)
An upper first electrode extending from the bottom surface of the first electrode to the first surface and having a width smaller than that of the first electrode,
The photodetector according to (1) above, further comprising an insulating upper pixel separation layer provided on the side surface of the upper first electrode.
(3)
The photodetector according to (1) or (2) above, wherein the first electrode and the pixel separation layer are provided between adjacent photoelectric conversion units.
(4)
The photodetector according to (3) above, wherein the first electrode is electrically connected to the first region of each of the adjacent photoelectric conversion units at the bottom surface.
(5)
The light according to any one of (1) to (4) above, wherein the formation depth of the first electrode from the second surface is deeper than the formation depth of the second region from the second surface. Detection device.
(6)
The photodetector according to any one of (1) to (5) above, further comprising a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film.
(7)
The photodetector according to (6) above, wherein the gate electrode is a vertical gate electrode provided by digging the semiconductor substrate in the thickness direction.
(8)
(1) to (7) above, the first conductive type potential control region, which is provided on the second surface side of the semiconductor substrate with the second region and an insulating layer interposed therebetween and can control the potential. The photodetector according to any one of the above.
(9)
The photodetector according to any one of (1) to (8) above, wherein the formation depths of the first region and the second region in the thickness direction of the semiconductor substrate are different for each photoelectric conversion unit. ..
(10)
The photodetector according to any one of (1) to (9) above, further comprising a multilayer wiring layer laminated on the second surface of the semiconductor substrate.
(11)
The photodetector according to (10) above, wherein the multilayer wiring layer includes a light-shielding structure extending in the in-plane direction of the semiconductor substrate.
(12)
The photodetector according to any one of (1) to (11) above, which is provided on the first surface of the semiconductor substrate and further includes an uneven structure for scattering or diffracting the incident light.
(13)
The second conductive type floating diffusion region provided on the second surface side of the semiconductor substrate, and the floating diffusion region.
(1) to (12), further including a transfer gate transistor provided between the second region and the floating diffusion region and controlling the transfer of electric charges from the second region to the floating diffusion region. The photodetector according to any one of the above.
(14)
The second conductive type overflow / drain region provided on the side opposite to the floating diffusion region with the second region interposed therebetween.
The light according to (13) above, further comprising an overflow gate transistor provided between the second region and the overflow drain region and controlling the transfer of electric charges from the second region to the overflow drain region. Detection device.
(15)
Further provided with a pinning layer provided at the interface between the semiconductor substrate and the insulating material,
The photodetector according to any one of (1) to (14) above, wherein the pinning layer is a chargeable layer or the second conductive type layer.
(16)
A fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
The photodetector according to any one of (1) to (15) above, further comprising an insulating layer that surrounds the bonding surface between the second region and the fourth region in the in-plane direction of the semiconductor substrate. ..
(17)
A fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
Any one of (1) to (15) above, further comprising a fifth region of the second conductive type provided in contact with the first region on the second surface side of the first region. The photodetector according to.
(18)
The plurality of photoelectric conversion units include the photoelectric conversion unit of a reference pixel provided with a light-shielding portion on the incident surface of the incident light, and the photoelectric conversion unit of a normal pixel not provided with the light-shielding portion. The photodetector according to any one of 1) to (17).
(19)
The photodetector according to (18) above, wherein the reference pixel is provided adjacent to the normal pixel.
(20)
The photodetector according to any one of (1) to (19) above, wherein the first electrode is a cathode electrode and the second electrode is an anode electrode.

(30)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
The first region of the first conductive type provided on the first surface side of the semiconductor substrate and
A second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and
A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and
A third electrode and a fourth electrode extending from the second surface in the thickness direction of the semiconductor substrate,
A plurality of through insulating layers extending from the bottom surface of each of the third electrode and the fourth electrode to the first surface and having a width smaller than that of the third electrode and the fourth electrode.
An insulating pixel separation layer provided on each side surface of the third electrode and the fourth electrode, and
The second conductive type potential control region that is electrically connected to the bottom surface of the third electrode exposed from the through insulating layer, and
The first conductive type reset region that is electrically connected to the bottom surface of the fourth electrode exposed from the through insulating layer, and
A first electrode that is electrically connected to the first region from the first surface side,
A photodetector comprising a second electrode that is electrically connected to the second region from the second surface side.
(31)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode,
A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
A fourth region of the first conductive type provided in contact with the second region in the depth direction of the semiconductor substrate,
An insulating layer that surrounds the bonding surface between the second region and the fourth region in the in-plane direction of the semiconductor substrate.
A third conductive type third region provided on the semiconductor substrate and absorbing incident light,
A photodetector.
(32)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode,
A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
On the side where the second region is provided with respect to the first region, the fifth region of the second conductive type provided in contact with the first region and
On the side where the first region is provided with respect to the second region, the fourth region of the first conductive type provided in contact with the second region and
A third conductive type third region provided in a region between the fourth region and the fifth region of the semiconductor substrate and absorbing incident light, and
A photodetector.
(33)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
A first conductive type region provided on the semiconductor substrate and electrically connected to the first electrode,
A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and
A photodetector comprising a surface corresponding to the third region of the semiconductor substrate and a layer having a chargeability at an interface with an insulating material or a pinning layer provided as the second conductive type layer.
(34)
Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
The photoelectric conversion unit
A first conductive type region provided on the first surface side of the semiconductor substrate and electrically connected to the first electrode,
A second conductive type second region provided on the second surface side of the semiconductor substrate opposite to the first surface and electrically connected to the second electrode.
A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and
The second conductive type floating diffusion region provided on the second surface side of the semiconductor substrate, and the floating diffusion region.
A photodetector comprising a transfer gate transistor provided between the second region and the floating diffusion region to control charge transfer from the second region to the floating diffusion region.
(35)
The first region of the first conductive type provided on the semiconductor substrate and electrically connected to the first electrode,
A second conductive type second region provided on the semiconductor substrate separated from the first region and electrically connected to the second electrode.
A plurality of photoelectric conversion units provided in a region between the first region and the second region of the semiconductor substrate and including a third conductive type third region that absorbs incident light are provided.
The plurality of photoelectric conversion units include the photoelectric conversion unit of a reference pixel provided with a light-shielding portion on the incident surface of the incident light, and the photoelectric conversion unit of a normal pixel not provided with the light-shielding portion.
The reference pixel is a photodetector provided adjacent to the normal pixel.
　本出願は、米国特許商標庁において、２０１９年７月１２日に出願された米国特許仮出願番号第６２／８７３５２７号、２０１９年７月３０日に出願された米国特許仮出願番号第６２／８８０２１４号、２０１９年７月３０日に出願された米国特許仮出願番号第６２／８８０４９７号を基礎として優先権を主張するものであり、この出願のすべての内容を参照によって本出願に援用する。 This application is filed at the US Patent and Trademark Office with US Patent Provisional Application No. 62/873527 filed on July 12, 2019, and US Patent Provisional Application No. 62/880214 filed on July 30, 2019. No., which claims priority on the basis of US Patent Provisional Application No. 62/880497 filed on July 30, 2019, and the entire contents of this application are incorporated herein by reference.
　当業者であれば、設計上の要件や他の要因に応じて、種々の修正、コンビネーション、サブコンビネーション、および変更を想到し得るが、それらは添付の請求の範囲やその均等物の範囲に含まれるものであることが理解される。 Those skilled in the art may conceive of various modifications, combinations, sub-combinations, and changes, depending on design requirements and other factors, which are included in the appended claims and their equivalents. It is understood that it is.

Claims (20)

  1. 　半導体基板に設けられた複数の光電変換部
    を備え、
    　前記光電変換部は、
    　前記半導体基板の第１面側に設けられた第１導電型の第１領域と、
    　前記半導体基板の前記第１面と反対の第２面側に設けられた第２導電型の第２領域と、
    　前記半導体基板の前記第１領域と前記第２領域との間の領域に設けられ、入射光を吸収する第３導電型の第３領域と、
    　前記第２面から前記半導体基板の厚み方向に延在し、底面にて前記第１領域と電気的に接続する第１電極と、
    　前記第１電極の側面に設けられた絶縁性の画素分離層と、
    　前記第２面側から前記第２領域と電気的に接続する第２電極と
    を備える、光検出装置。     Equipped with a plurality of photoelectric conversion units provided on a semiconductor substrate,
    The photoelectric conversion unit
    The first region of the first conductive type provided on the first surface side of the semiconductor substrate and
    A second region of the second conductive type provided on the second surface side opposite to the first surface of the semiconductor substrate, and
    A third conductive type third region provided in a region between the first region and the second region of the semiconductor substrate and absorbing incident light, and
    A first electrode extending from the second surface in the thickness direction of the semiconductor substrate and electrically connecting to the first region on the bottom surface,
    An insulating pixel separation layer provided on the side surface of the first electrode and
    A photodetector comprising a second electrode that is electrically connected to the second region from the second surface side.
  2. 　前記第１電極の底面から前記第１面まで延在し、前記第１電極よりも幅が小さい上部第１電極と、
    　前記上部第１電極の側面に設けられた絶縁性の上部画素分離層と
    をさらに備える、請求項１に記載の光検出装置。     An upper first electrode extending from the bottom surface of the first electrode to the first surface and having a width smaller than that of the first electrode,
    The photodetector according to claim 1, further comprising an insulating upper pixel separation layer provided on the side surface of the upper first electrode.
  3. 　前記第１電極及び前記画素分離層は、隣接する前記光電変換部の間に設けられる、請求項１に記載の光検出装置。 The photodetector according to claim 1, wherein the first electrode and the pixel separation layer are provided between adjacent photoelectric conversion units.
  4. 　前記第１電極は、隣接する前記光電変換部の各々の前記第１領域と前記底面にて電気的に接続する、請求項３に記載の光検出装置。 The photodetector according to claim 3, wherein the first electrode is electrically connected to the first region of each of the adjacent photoelectric conversion units on the bottom surface.
  5. 　前記第１電極の前記第２面からの形成深さは、前記第２領域の前記第２面からの形成深さよりも深い、請求項１に記載の光検出装置。 The photodetector according to claim 1, wherein the formation depth of the first electrode from the second surface is deeper than the formation depth of the second region from the second surface.
  6. 　前記半導体基板の前記第２面にゲート絶縁膜を介して設けられたゲート電極をさらに備える、請求項１に記載の光検出装置。 The photodetector according to claim 1, further comprising a gate electrode provided on the second surface of the semiconductor substrate via a gate insulating film.
  7. 　前記ゲート電極は、前記半導体基板を厚み方向に掘り込んで設けられた縦型ゲート電極である、請求項６に記載の光検出装置。 The photodetector according to claim 6, wherein the gate electrode is a vertical gate electrode provided by digging the semiconductor substrate in the thickness direction.
  8. 　前記半導体基板の前記第２面側に、前記第２領域と絶縁層を挟んで設けられ、電位を制御可能な前記第１導電型のポテンシャル制御領域をさらに備える、請求項１に記載の光検出装置。 The photodetection according to claim 1, further comprising the first conductive type potential control region which is provided on the second surface side of the semiconductor substrate with the second region and an insulating layer interposed therebetween and can control the potential. apparatus.
  9. 　前記半導体基板の厚み方向における前記第１領域及び前記第２領域の形成深さは、前記光電変換部ごとにそれぞれ異なる、請求項１に記載の光検出装置。 The photodetector according to claim 1, wherein the formation depths of the first region and the second region in the thickness direction of the semiconductor substrate are different for each photoelectric conversion unit.
  10. 　前記半導体基板の前記第２面に積層された多層配線層をさらに備える、請求項１に記載の光検出装置。 The photodetector according to claim 1, further comprising a multilayer wiring layer laminated on the second surface of the semiconductor substrate.
  11. 　前記多層配線層は、前記半導体基板の面内方向に広がる遮光構造を含む、請求項１０に記載の光検出装置。 The photodetector according to claim 10, wherein the multilayer wiring layer includes a light-shielding structure extending in the in-plane direction of the semiconductor substrate.
  12. 　前記半導体基板の前記第１面に設けられ、前記入射光を散乱又は回折させる凹凸構造をさらに備える、請求項１に記載の光検出装置。 The photodetector according to claim 1, further comprising a concavo-convex structure provided on the first surface of the semiconductor substrate to scatter or diffract the incident light.
  13. 　前記半導体基板の前記第２面側に設けられた前記第２導電型のフローティングディフュージョン領域と、
    　前記第２領域と、前記フローティングディフュージョン領域との間に設けられ、前記第２領域から前記フローティングディフュージョン領域への電荷の転送を制御する転送ゲートトランジスタと
    をさらに備える、請求項１に記載の光検出装置。     The second conductive type floating diffusion region provided on the second surface side of the semiconductor substrate, and the floating diffusion region.
    The photodetector according to claim 1, further comprising a transfer gate transistor provided between the second region and the floating diffusion region and controlling the transfer of electric charges from the second region to the floating diffusion region. apparatus.
  14. 　前記第２領域を挟んで前記フローティングディフュージョン領域と反対側に設けられた前記第２導電型のオーバーフロードレイン領域と、
    　前記第２領域と、前記オーバーフロードレイン領域との間に設けられ、前記第２領域から前記オーバーフロードレイン領域への電荷の転送を制御するオーバーフローゲートトランジスタと
    をさらに備える、請求項１３に記載の光検出装置。     The second conductive type overflow / drain region provided on the side opposite to the floating diffusion region with the second region interposed therebetween.
    The photodetector according to claim 13, further comprising an overflow gate transistor provided between the second region and the overflow / drain region and controlling the transfer of electric charges from the second region to the overflow / drain region. apparatus.
  15. 　前記半導体基板と、絶縁性材料との界面に設けられたピニング層をさらに備え、
    　前記ピニング層は、帯電性を有する層、又は前記第２導電型の層である、請求項１に記載の光検出装置。     Further provided with a pinning layer provided at the interface between the semiconductor substrate and the insulating material,
    The photodetector according to claim 1, wherein the pinning layer is a chargeable layer or the second conductive type layer.
  16. 　前記第２領域よりも前記第１面側に、前記第２領域と接して設けられた前記第１導電型の第４領域と、
    　前記第２領域と前記第４領域との接合面を前記半導体基板の面内方向にて囲む絶縁層と
    をさらに備える、請求項１に記載の光検出装置。     A fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
    The photodetector according to claim 1, further comprising an insulating layer that surrounds the bonding surface between the second region and the fourth region in the in-plane direction of the semiconductor substrate.
  17. 　前記第２領域よりも前記第１面側に、前記第２領域と接して設けられた前記第１導電型の第４領域と、
    　前記第１領域よりも前記第２面側に、前記第１領域と接して設けられた前記第２導電型の第５領域と
    をさらに備える、請求項１に記載の光検出装置。     A fourth region of the first conductive type provided in contact with the second region on the first surface side of the second region.
    The photodetector according to claim 1, further comprising a fifth region of the second conductive type provided in contact with the first region on the second surface side of the first region.
  18. 　複数の前記光電変換部は、前記入射光の入射面に遮光部が設けられた参照画素の前記光電変換部と、前記遮光部が設けられない通常画素の前記光電変換部とを含む、請求項１に記載の光検出装置。 The plurality of photoelectric conversion units include the photoelectric conversion unit of a reference pixel provided with a light-shielding portion on an incident surface of the incident light, and the photoelectric conversion unit of a normal pixel not provided with the light-shielding portion. The photodetector according to 1.
  19. 　前記参照画素は、前記通常画素と隣接して設けられる、請求項１８に記載の光検出装置。 The photodetector according to claim 18, wherein the reference pixel is provided adjacent to the normal pixel.
  20. 　前記第１電極はカソード電極であり、前記第２電極はアノード電極である、請求項１に記載の光検出装置。 The photodetector according to claim 1, wherein the first electrode is a cathode electrode and the second electrode is an anode electrode.
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